WO2025186835A1

WO2025186835A1 - A bioresorbable cardiovascular stent (bcs) and its method of preparation thereof

Info

Publication number: WO2025186835A1
Application number: PCT/IN2025/050323
Authority: WO
Inventors: Dharmendra Kumar Tyagi; Dhiraj K. MAHAJAN
Original assignee: Indian Institute Of Technology Ropar
Current assignee: Indian Institute Of Technology Ropar
Priority date: 2024-03-06
Filing date: 2025-03-06
Publication date: 2025-09-12
Anticipated expiration: 2026-09-06
Also published as: WO2025186835A8

Abstract

The present invention discloses a bioresorbable cardiovascular stent (100). The bioresorbable cardiovascular stent (100) comprising at least one strut (104) (110) connecting the plurality of rhombus-shaped cells (102) in both the longitudinal directions and the circumferential directions and each strut (104) (110) provided with a consistent thickness (108) and width (106). The stent (100) maintains a uniform thickness (108) throughout its length, and featuring struts (104, 110) with consistent thickness (108). The stent (100) is manufactured by using a micro-injection molding process with a single sprue-less hot runner gate. The bioresorbable cardiovascular stent (100) is configured to maintain structural integrity, biocompatible properties, improve radial stiffness to (612 kPa/mm) and radial strength to (225 kPa).

Description

A BIORESORBABLE CARDIOVASCULAR STENT (BCS) AND ITS METHOD OF PREPARATION THEREOF

CROSS REFERENCE TO RELATED APPLICATION AND PRIORITY

[0001] The present invention claims priority from Indian patent application 202411015887 filed on date 06^th March 2024.

FIELD OF THE INVENTION

[0002] The present invention relates to the field of an additive manufacturing. More particularly, the invention relates to a bioresorbable cardiovascular stent and its method of preparation thereof.

BACKGROUND OF THE INVENTION

[0003] A bioresorbable stent is a promising alternative to traditional stents. The bioresorbable stents are usually made from bioabsorbable materials such as bioabsorbable metals like magnesium or bioabsorbable polymers like a poly- lactic acid (PLA), a polycarbonate (PCL), or a polydioxanone. The bioresorbable stents support the vessel temporarily before breaking down overtime. This reduces problems like late inflammation, artifacts in clinical images, and the need for long-term antiplatelet treatment. The conventional stent differs in terms of structures, manufacturing methods, and composition. [0004] The advancement of conventional polymeric bioresorbable stents faces numerous challenges, encompassing issues about size, shape, melting temperature, conductivity, and surface finish. These challenges impose required constraints on the suitability of conventional metallic stent manufacturing techniques, such as knitting, welding, and braiding. While alternative methods like a photochemical etching, an electroforming, a laser cutting technology, a powder metallurgy, and an additive manufacturing methods are available. Each approach presents its own set of pros and cons. The laser-cutting technology is widely used over the past decade due to its rapidity, precision, cost-effectiveness, and reliability. The powder metallurgy introduces an innovative perspective for creating porous iron-based biodegradable stents.

[0005] The bioresorbable stents are considered as the next generation of stents. The development of stents are a challenging and costly process. The mechanical strength of polymers are comparatively less than that of metals. The strength of the stent depends on its material as well as shape. Recently, the laser cutting technology is extensively used for the manufacturing a metallic stent and the bioresorbable stent. The Laser cutting technology is best suitable for the metallic stents. Whereas the laser cutting technology creates limitations in case of the polymeric stents due to the low melting temperature. Further, during crafting of the stent using laser cutting the user first needs to generate a tube-like structure from the material before employing the laser for profile cutting. Hence, the laser cutting technology is a multi-step process which increases complexity.

[0006] Hence to overcome the aforesaid drawbacks an efficient cardiovascular stent is required.

OBJECTS OF THE INVENTION

[0007] Main object of the present disclosure is to provide a bioresorbable cardiovascular stent to manufacture a single piece bioresorbable cardiovascular stent.

[0008] Another object of the present disclosure is to provide the bioresorbable cardiovascular stent to implement plurality of rhombus or diamond-shaped cells interconnected to each other through at least one straight links/connectors.

[0009] Yet another object of the present disclosure is to provide the bioresorbable cardiovascular stent to facilitate interconnected plurality of cells in circumferential as well as longitudinal directions.

[0010] Another object of the present disclosure is to provide the bioresorbable cardiovascular stent to manufacture a single-piece bioresorbable cardiovascular stent using a micro-injection molding machine.

[0011] Yet another object of the present disclosure is to provide the bioresorbable cardiovascular stent to facilitate a micro-injection molding machine with a single hot runner gate.

[0012] Another object of the present disclosure is to provide the bioresorbable cardiovascular stent to reduce cavity fill pressure by using a mould with a less cavity hot runner.

[0013] Yet another object of the present disclosure is to provide the bioresorbable cardiovascular stent to reduce production costs.

[0014] Another object of the present disclosure is to provide the bioresorbable cardiovascular stent to maintain structural integrity and biocompatible properties.

[0015] Yet another object of the present disclosure is to provide the bioresorbable cardiovascular stent to improve radial stiffness to (612 kPa/mm) and radial strength to (225 kPa). [0016] Another object of the present disclosure is to provide the bioresorbable cardiovascular stent to minimize the wastage of material.

[0017] Yet another object of the present disclosure is to provide the bioresorbable cardiovascular stent to reduce dimensional fluctuation.

[0018] Another object of the present disclosure is to provide the bioresorbable cardiovascular stent to implement uniform thickness throughout the stent.

[0019] Yet another object of the present disclosure is to provide the bioresorbable cardiovascular stent to optimize performance.

SUMMARY OF THE INVENTION

[0020] Before the present a bioresorbable cardiovascular stent is described, it is to be understood that this application is not limited to a particular the bioresorbable cardiovascular stent as there may be multiple possible embodiments, which are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular implementations, versions, or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to the bioresorbable cardiovascular stent. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

[0021] The present invention discloses a bioresorbable cardiovascular stent comprises plurality of cells in the circumferential directions. The single piece stent structure comprising plurality of rhombus or diamond shaped cells structure. The plurality of cells are connected to each other by at least one straight links/connector both in a circumferential as well as in a longitudinal direction. The thickness and width of the plurality of cells are 0.2 millimeters (mm). Each cell comprises four edges. The length of each edge of plurality of rhombus or diamond shape cells are 1.16 mm. The inner diameter of the cell is 2.6 mm. The inner radius of the stent structure is 1.3 mm. The outer radius of the stent structure is 1.5 mm. The total length of the straight connector around circumference is 0.62 mm. The total length of the stent structure is 13.9 mm. The stent structure maintains a uniform thickness throughout its length. The stent structure is manufactured with a micro-injection molding method and a single hot runner gate. The method provides the required radial stiffness and radial strength.

[0022] A bioresorbable cardiovascular stent (BCS) comprises a lattice structure composed of a plurality of cells arranged in both circumferential and longitudinal directions, wherein each cell is shaped as a rhombus or diamond and has consistent, predefined dimensions. The stent includes at least one stmt positioned at the intersections of the cells, configured to connect the cells in both longitudinal and circumferential directions, with the stmts having a consistent thickness and width. The cells and stmts are formed from a poly lactic acid (PLA) and tri-ethyl citrate (TEC) composite, with TEC present in a weight percentage ranging from 5% to 30% of the total composition, ensuring flexibility and bioresorbability. The uniformly distributed rhombus or diamond-shaped cells and straight stmts ensure symmetry and facilitate mold fabrication. The lattice stmcture is fabricated as a single unit through micro-injection molding using a custom mold, without requiring assembly of separate parts, thereby ensuring structural integrity and manufacturing efficiency.

[0023] In an embodiment the present invention provides a thickness and width of the stmts in the range of 0.05-0.2 millimeters (mm)

[0024] In yet another embodiment the present invention provides a length (A) of each edge of the rhombus-shaped cell is in the range of 0.5-1.5 mm and a total length of the stent is in the range of 5-25 mm.

[0025] In yet another embodiment the present invention provides an inner diameter of each rhombus-shaped cell is in the range of 2-3 mm, and the outer radius (E) of each rhombus-shaped cell is 1.5 mm.

[0026] In yet another embodiment the present invention provides a total length of the stmt around the circumference is 0.62 mm.

[0027] In yet another embodiment the present invention provides the rhombus or diamond shaped cells, which are configured to optimize strength-to-weight ratio.

[0028] In still another embodiment the present invention provides the stmts form integral nodes at intersections, with each node joining at least three sides of the rhombusshaped cells.

[0029] In yet another embodiment the present invention provides the stmts, which are formed from a material selected from metal, composite, or polymer.

[0030] In yet another embodiment the present invention provides the stmts include a hollow or porous stmcture to reduce weight.

[0031] In yet another embodiment the present invention provides a method for preparing a bioresorbable cardiovascular stent (BCS) comprises drying poly lactic acid (PLA) at a temperature of 60°C for 24 hours to remove moisture. The dried PLA is then blended with tri-ethyl citrate (TEC) at a temperature of 190°C for 7 minutes at a rotation speed of 30 rpm, wherein TEC is present in varying weight percentages ranging from 5% to 30% of the total blend. A stent geometry is created using computer-aided design (CAD) software, incorporating uniformly distributed diamond-shaped cells and straight connectors to ensure symmetry and facilitate mold fabrication. A custom mold, specifically designed for the stent geometry, is fabricated with a hot-runner system to enable net-shape manufacturing. The PLA-TEC composite materials undergo mechanical, thermal, and meltflow testing to determine the optimal composition for stent application. The optimal PLA- TEC composite is then injected into the custom mold using a micro-injection molding machine, with a clamping capacity of 10 tons and a maximum injection pressure of 250 MPa, wherein the injection parameters are refined based on melt-flow simulations to ensure precise filling of the stent cavity. The stent is produced in a single machining process without the need for assembling separate parts, ensuring it is formed as a complete unit. Post-processing is performed to achieve the desired specifications, including cutting and trimming as necessary. Finally, quality control checks are conducted on the molded stent to ensure compliance with biocompatibility and structural integrity standards.

BRIEF DESCRIPTION OF DRAWINGS

[0032] The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawings. To illustrate the disclosure, there is shown in the present document example constructions of the disclosure. The detailed description is described with reference to the following accompanying figures.

[0033] Figure 1 illustrates a three-dimensional (3D) isometric view of a bioresorbable cardiovascular stent, in a preferred embodiment of the present invention.

[0034] Figure 2 illustrates a three-dimensional (3D) exploded view of a bioresorbable cardiovascular stent, in a preferred embodiment of the present invention.

[0035] Figure 3 illustrates a dimension of the bioresorbable cardiovascular stent, in a preferred embodiment of the present invention.

[0036] Figure 4 illustrates a side view of a bioresorbable cardiovascular stent, in a preferred embodiment of the present invention.

[0037] Figure 5 illustrates the top and bottom view of the bioresorbable cardiovascular stent, in a preferred embodiment of the present invention.

[0038] Figure 6 illustrates an isometric view of a bioresorbable cardiovascular stent, in a preferred embodiment of the present invention. [0039] Figure 7(a) illustrates the method steps for preparing various Poly lactic Acid (PLA) and Triethyl Citrate (TEC) composites, illustrating key steps for material blending, drying and palletization, in a preferred embodiment of the present invention.

[0040] Figure 7(b) illustrates the structure of TEC, in a preferred embodiment of the present invention.

[0041] Figure 7(c) illustrates the structure of PLA, in a preferred embodiment of the present invention.

[0042] Figure 8 illustrates a flow chart representing the detailed steps for BCS fabrication by using a microinjection molding, in a preferred embodiment of the present invention.

[0043] Figure 9 illustrates a flow chart for fabricating bioresorbable cardiovascular stent, in a preferred embodiment of the present invention.

[0044] The figure depicts various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

[0045] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising", “having”, and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words are not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any devices and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, devices and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.

[0046] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated, but is to be accorded the widest scope consistent with the principles and features described herein. [0047] Following is a list of elements and reference numerals used to explain various embodiments of the present subject matter.

Equivalents

[0048] The present invention discloses a bioresorbable cardiovascular stent (100) as shown in Figure 1. The bioresorbable cardiovascular stent structure (100) is a single piece bioresorbable stent (100). The stent (100) comprises plurality of cells (102) in a circumferential directions and longitudinal directions. The number of cells (102) varies along with its length to obtain a desired length. The shape of the plurality of cells (102) of the stent (100) is a rhombus or diamond shape. The plurality of cells (102) are connected to each other by at least one strut (104) (110) both in the circumferential as well as in a longitudinal direction. In an embodiment, the strut ( 104) (110) may be referred to as straight connector/straight link. The thickness of the struts (104, 110) are consistent. The rhombus shape of cell includes parallel opposite edges and equal opposite angles. All the edges of a rhombus are equal in length, and the diagonals bisect each other at right angles.

[0049] Now referring to Figure 2, Figure 2 relates to the three-dimensional (3D) exploded view of a bioresorbable cardiovascular stent. The stent comprising plurality of rings (101). Each ring comprising plurality of cells. Each cells are interconnected to each other in circumferential direction as well as in longitudinal directions. Plurality of rings are interconnected by using strut in circumferential direction. The rhombus shape of cell includes parallel opposite edges and equal opposite angles. All the edges of a rhombus are equal in length, and the diagonals bisect each other at right angles.

[0050] Now referring to Figure 3, Figure 3 relates to the workable ranges of dimensions of the bioresorbable cardiovascular stent (200) as shown in below Table 1. The thickness (108) (as shown in Figure 1) and width (106) (B) of the plurality of cells (102) are in the range of 0.05-0.2 millimeters (mm) and more specifically 0.2 mm. The stent (100) comprises the plurality of rhombus or diamond-shaped cells (102). Each cell (102) includes four edges. The length (A) of each edge of the plurality of cells (102) are in the range of 0.5-1.5 mm and more specifically 1.16 mm. The total length (C) of the straight connector around the circumference (110) is 0.62 mm. The inner diameter of the cell (102) is in the range of 2-3 mm and more specifically 3 mm. The inner radius (D) of the cell (102) is 1.3 mm. The outer radius (E) of the cell (102) is 1.5 mm. The total length of the stent (100) is in the range of 5-25 mm and more specifically 13.9 mm.

Rinner (D) = 1.3 mm

Router (E) = 1.3 mm (inner radius (D)) +0.2 mm (thickness (B)) = 1.5 mm

Table 1: Details of workable ranges of parameters of stent

[0051] In an embodiment, the structure for the bioresorbable stent (300) is manufactured with medical-grade bioresorbable material. The structure of the stent (100) is selected based on a mold flow and a FEA simulation results. A structural simulation is for analyzing the mechanical performance of the stent based on structural parameters such as elastic recoil, dogboning, longitudinal retraction, maximum stress, and otherwise. A mold flow simulation provides an understanding of the manufacturing of the stents using the injection molding method. The mold flow simulation determines whether the selected structural processing parameters are sufficient to fill the stent structure. The structural configuration of a stent (100) is providing performance parameters such as radial strength, compression strength, flexibility, and degradation. The bioabsorbable cardiovascular stent achieves radial strength (225 kPa) and radial stiffness (612 kPa/mm). The stent structure (100) provides bioengineering advancements with potential transformative implications for medical devices and patient care. The stent structure (100) provides very low tolerance specifically 10 microns for the dimensions of the stent. [0052] In an embodiment, the medical-grade bioresorbable materials composites enhance the mechanical strength and radiopacity of stents (100). The material structure of stents (100) are modified to improve rheological properties of the stent (100).

[0053] Now referring to Figure 4, Figure 4 relates to the top view of bioresorbable cardiovascular stent (100) manufactured in a single step with the micro-injection molding method. The micro-injection molding method comprises a micro-injection molding machine with a four sliders, a single gate opening and a single hot runner. The micro-injection molding process is used to create balloon-expandable peripheral polycaprolactone (PCL) stents (100). Figure 5 illustrates the top and bottom view of the bioresorbable cardiovascular stent, in a preferred embodiment of the present invention.

Figure 6 illustrates an isometric view of a bioresorbable cardiovascular stent, in a preferred embodiment of the present invention.

[0054] In an embodiment, the exhaustive finite element analysis (FEA) is performed on plurality stents (100) to provide optimal results and required radial strength. The FEA simulation is conducted by using ABAQUS. The mold flow simulation is conducted by using Moldex3D.

[0055] Now referring to Figure 7(a), Figure 7(a) illustrates the method steps for preparing various PLA-TEC composites, illustrating key steps for material blending, drying and palletization. The methodology adopted for preparing various PLA-TEC composites, for fabrication a bioresorbable cardiovascular stent (BCS) is illustrated further. In an embodiment, the Poly lactic acid (PLA) is used for fabricating a net-shape braided composite stent (BCS).

[0056] Figure 7(b) illustrates the structure of TEC and Figure 7(c) illustrates the structure of PLA. The medical-grade PLA is procured from 2M Biotec LLP. This material represents a biodegradable polymer characterized by a glass transition temperature ranging from 60 to 65°C and a melting temperature spanning from 150 to 155°C. The PLA is a highly viscous material with an MFI typically around 3.0 g/ 10 min, which is insufficient for completely filling the stent geometry using micro-injection molding. For injection molding, an MFI in the range of 10-30 g/10 min is desirable. Therefore, the modifications are necessary to increase the MFI of PLA while preserving its biodegradable properties. The proposed stent is manufactured from composition of PLA and. The PLA is subjected to a drying process for 24 hours at 60 °C before mixing with the TEC. Subsequently, the PLA is homogeneously blended with plasticizers i.e., TEC. The blending process is carried out at a temperature of 190 °C for a duration of 7 minutes, with a blend rotation speed of 30 rpm. The plasticizer TEC is incorporated into the PLA matrix with different combination of weight percentages. The PLA is modified with a bio-based plasticizer i.e., tri-ethyl citrate (TEC). Various compositions of PLA-TEC composites (ranging from 5%to 30% TEC) may be formulated and tested, as shown in Table 2 for fabricating net-shaped BCS.

Table 2: Compositions of various PLA-TEC

[0057] In an embodiment, the processing or manufacturing steps of stents (100) such as a mixing, a drying, and the cutting, the material is executed within a controlled environment. The manufacturing steps regulates the biocompatible properties of stent (100). The composition of bio-polymer material or mould is filled in the micro-injection molding machine to manufacture the stent structure (100). The method is designed in such way that the stent structure (100) is manufactured without any defects.

[0058] Now referring to Figure 8, the Figure 8 illustrates a flow chart representing the detailed steps for BCS fabrication by using a microinjection molding. The fabrication of a novel net-shaped bioresorbable cardiovascular stent (BCS) geometry by using microinjection molding (pIM) involved several key steps which are illustrated further:

[0059] Step- 1 : Stent Geometry creation is illustrated further. In an embodiment, for the fabrication of BCS geometry, the closed-cell stent designs are constructed by using Solidworks 2018. The stent design featured uniformly distributed diamond-shaped cells and straight connectors along both longitudinal and circumferential axes. An even number of repeating cells ranging from (0-8) around the circumference ensured symmetry and simplified mold fabrication.

[0060] Step-2: Performance analysis: The method further perform two types of simulation analysis i.e., structural analysis and melt flow analysis. In an embodiment, the structural analysis of the BCS is illustrated further. The structural integrity of the geometries are assessed through crimping, expansion, and bending analyses using Finite Element software, ABAQUS/Standard. In an embodiment, the Melt-flow analysis is done by using Moldex3D R17 for evaluating the manufacturability of various stent geometries via microinjection molding. This analysis utilized principles of mass, momentum, and energy conservation to predict flow patterns and detect potential defects like short shots or flash during the filling and packaging stages.

[0061] Step-3: Mold fabrication: A custom-made mold with a hot-runner system is designed and constructed specifically for the selected BCS geometry (0-8-cell, 0-8 ring configuration with straight connectors, 3.0 mm diameter, 0.2 mm strut thickness (108), and 13.9 mm length), facilitating net-shape manufacturing of BCS based on the stent design.

[0062] Step-4: Material modification: The PLA was modified with a bio-based plasticizer, tri -ethyl citrate (TEC). Various compositions of PLA-TEC composites (ranging from 5% to 30% TEC) are formulated and tested, as outlined in Table 2. Figure 7(a) illustrates the methodology used for preparing these composites, involving material blending, drying, and palletization.

[0063] Step-5: Material characterization: The PLA-TEC composite materials are subjected to comprehensive mechanical, thermal, and melt-flow characterization to determine the optimal composition for BCS application.

[0064] Step-6: Material utilization and BCS fabrication: The optimal PLA-TEC composition are identified and the BCS samples are fabricated by using a microinjection molding machine. The microinjection molding machine is having 10-ton clamping capacity and a maximum injection pressure of 250 MPa. The micro-injection molding process parameters are refined based on melt-flow simulations conducted using Moldex3D software, ensuring precise stent cavity filling during micro-injection molding. This fabrication of bioresorbable cardiovascular stents with complex geometries, optimized for both structural performance and manufacturability using micro-injection molding process.

[0065] The micro-injection molding method comprises a micro-injection molding machine with a four sliders, a single gate opening and a single hot runner. The microinjection molding process is used to create balloon-expandable peripheral polycaprolactone (PCL) stents (100).

[0066] In an embodiment, the micro-injection molding machine is constructed with two-plate mold and four sliders. The micro-injection molding machine comprising a mold equipped with four sliders and a single hot runner system. The micro-injection molding machine consisting sprue-less hot runner technology in conjunction with a mold temperature controller. The micro-injection molding machine regulates the temperature of the mold. The micro-injection machine ensures that the mold remains within the specified range throughout the entire manufacturing process of the stent (100). The micro-injection molding machine manufactures stents (100) with the required precision and reliability. The micro- injection molding method makes less cost-effective bioresorbable cardiovascular stents (100). The micro-injection molding method is solving problems related to the size, shape, and surface finish of traditional stents. The micro-injection molding method also provides a quick and cheap way to create complex structures of stents (100).

[0067] In an embodiment, the micro-injection molding process manufactures the bioresorbable stent (100) as in single step with high precision. The traditional laser cutting production rate is very slow comparatively injection molding production rate is higher. The automate setup of micro-injection molding is producing stents (100) on a mass scale.

[0068] In an embodiment, the manufacturing of stent structure (100) through injection molding is challenging with more than four sliders. The development of actual stent structure (100) through injection molding with four sliders are convenient. The utilization of a higher number of sliders (i.e., more than four sliders) with micro-injection molding machine increases the risk of molding defects such as flash, parting line issues, under filling, and weld lines. Micro-injection molding machine ejects the part from the mold without defects with less than four sliders.

[0069] Figure 9 illustrates a flow chart performing a method for preparing bioresorbable cardiovascular stent, in accordance with an embodiment of the present subject matter. The order in which the method (900) is described is not intended to be construed as a limitation, and any number of the described method blocks may be combined in any order to implement the method (900) or alternate methods. Additionally, individual blocks may be deleted from the method (900) without departing from the spirit and scope of the subject matter described herein. Furthermore, the method may be implemented in any suitable hardware, software, firmware, or combination thereof. However, for ease of explanation, in the embodiments described below, the method (900) may be considered to be implemented as described in the stent (100).

[0070] At block 902, drying poly lactic acid (PLA) at a temperature of 60°C for a duration of 24 hours to remove moisture.

[0071] At block 904, blending the dried PLA with tri-ethyl citrate (TEC) at a temperature of 190°C for a duration of 7 minutes at a rotation speed of 30 rpm, wherein the TEC is present in varying weight percentages ranging from 5% to 30% of the total blend.

[0072] At block 906, creating a stent geometry using computer-aided design (CAD) software, wherein the stent design features uniformly distributed diamond-shaped cells (102) and straight connectors, ensuring symmetry and facilitating mold fabrication. [0073] At block 908, fabricating a custom mold specifically designed for the stent geometry, incorporating a hot-runner system to facilitate net-shape manufacturing.

[0074] At block 910, configuring the PLA-TEC composite materials through mechanical, thermal, and melt-flow tests to determine the optimal composition for stent application.

[0075] At block 912, injecting the optimal PLA-TEC composite into the custom mold using a micro-injection molding machine, wherein the machine has a clamping capacity of 10 tons and a maximum injection pressure of 250 MPa, and wherein the injection parameters are refined based on melt-flow simulations to ensure precise filling of the stent cavity.

[0076] At block 914, producing the stent in a single machining process without the need for preparing separate parts, thereby ensuring the stent is formed as a complete unit.

[0077] At block 916, post-processing the molded stent to achieve desired specifications, including cutting and trimming as necessary.

[0078] At block 918, conducting quality control checks on the final stent to ensure compliance with biocompatibility and structural integrity standards.

[0079] Some embodiments of the present subject matter enable to provide the bioabsorbable cardiovascular stent to provide plurality of diamond or rhombus-shaped cells around the circumference and longitudinal direction.

[0080] Some embodiments of the present subject matter enable to provide the singlepiece bioabsorbable cardiovascular stent.

[0081] Some embodiments of the present subject matter enable to provide the bioresorbable cardiovascular stent to improve radial stiffness to (612 kPa/mm) and radial strength to (225 kPa).

[0082] Some embodiments of the present subject matter enable to provide the bioabsorbable cardiovascular stent to reduce cavity fill pressure reduce cavity fill pressure by using a mould with a less cavity hot runner.

[0083] Some embodiments of the present subject matter enable to provide the bioabsorbable cardiovascular stent to facilitate a micro-injection molding machine with a single hot runner gate.

[0084] Some embodiments of the present subj ect matter enable to manufacture a singlepiece bioresorbable cardiovascular stent using a micro-injection molding machine

[0085] Some embodiments of the present subject matter enable to provide the mould is filled in the micro-injection molding machine through a single gate opening. [0086] Some embodiments of the present subject matter enable to provide the bioabsorbable cardiovascular stent comprising bioresorbable/ bioabsorbable polymers.

[0087] Some embodiments of the present subject matter enable to provide the specific structure of the bioabsorbable cardiovascular stent and the mould. The specific structure of the stent and mould provides accurate shape, dimensions, and features to optimize high performance.

[0088] Some embodiments of the present subject matter enable to provide the bioresorbable cardiovascular stent to reduce production costs.

[0089] Some embodiments of the present subject matter enable to provide the bioresorbable cardiovascular stent to maintain structural integrity and biocompatible properties.

[0090] Some embodiments of the present subject matter enable to provide the bioabsorbable cardiovascular stent to minimize the wastage of material.

[0091] Some embodiments of the present subject matter enable to provide the bioabsorbable cardiovascular stent to reduce dimensional fluctuation.lt will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. [0092] Although implementations for bioresorbable cardiovascular stent (BCS) (100) and its method of preparation thereof have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features described. Rather, the specific features are disclosed as examples of implementation for the bioresorbable cardiovascular stent (BCS) and its method (900) of preparation thereof.

Claims

CLAIMS:

1. A bioresorbable cardiovascular stent (BCS) (100) comprising: a lattice structure composed of a plurality of cells (102) arranged in both circumferential and longitudinal directions, wherein each cell (102) is shaped as a rhombus or diamond and has consistent, predefined dimensions; at least one strut (104, 110) positioned at the intersections of the cells (102), configured to connect the cells (102) in both longitudinal and circumferential directions, wherein the struts (104, 110) have a consistent thickness (108) and width (106); and wherein the cells (102) and strut (104, 110) are formed from a poly lactic acid (PLA) and tri-ethyl citrate (TEC) composite, wherein TEC is present in a weight percentage ranging from 5% to 30% of the total composition, ensuring flexibility and bioresorbability; wherein the uniformly distributed rhombus or diamond-shaped cells (102) and straight struts (104, 110), ensuring symmetry and facilitating mold fabrication; and wherein the lattice structure is fabricated as a single unit through micro-injection molding using a custom mold, without requiring assembly of separate parts, ensuring structural integrity and manufacturing efficiency.

2. The bioresorbable cardiovascular stent (BCS) (100) as claimed in claim 1, wherein the thickness (108) and width (106) of the struts (104) (110) are in the range of 0.05-0.2 millimeters (mm)

3. The bioresorbable cardiovascular stent (BCS) (100) as claimed in claim 1, wherein the length (A) of each edge of the rhombus-shaped cell (102) is in the range of 0.5 -1.5 mm and a total length of the stent (100) is in the range of 5-25 mm.

4. The bioresorbable cardiovascular stent (BCS) (100) as claimed in claim 1, wherein an inner diameter of each rhombus-shaped cell (102) is in the range of 2-3 mm, and the outer radius (E) of each rhombus-shaped cell is 1.5 mm.

5. The bioresorbable cardiovascular stent (BCS) (100) as claimed in claim 1, wherein the total length of the strut (104) (110) around the circumference (110) is 0.62 mm.

6. The bioresorbable cardiovascular stent (BCS) (100) as claimed in claim 1, wherein the rhombus shaped cells (102) are configured to optimize strength-to-weight ratio.

7. The bioresorbable cardiovascular stent (BCS) (100) as claimed in claim 1, wherein the struts (104, 110) form integral nodes at intersections, with each node joining at least three sides of the rhombus-shaped cells (102).

8. The structural component as claimed in claim 1, wherein the struts (104, 110) are formed from a material selected from metal, composite, or polymer.

9. The structural component as claimed in claim 1, wherein the struts (104, 110) include a hollow or porous structure to reduce weight.

10. A method (900) for preparing a bioresorbable cardiovascular stent (BCS), comprising the steps of: drying poly lactic acid (PLA) at a temperature of 60°C for a duration of 24 hours to remove moisture; blending the dried PLA with tri-ethyl citrate (TEC) at a temperature of 190°C for a duration of 7 minutes at a rotation speed of 30 rpm, wherein the TEC is present in varying weight percentages ranging from 5% to 30% of the total blend; creating a stent geometry using computer-aided design (CAD) software, wherein the stent design features uniformly distributed diamond-shaped cells (102) and straight connectors, ensuring symmetry and facilitating mold fabrication; fabricating a custom mold specifically designed for the stent geometry, incorporating a hot-runner system to facilitate net-shape manufacturing; configuring the PLA-TEC composite materials through mechanical, thermal, and melt-flow tests to determine the optimal composition for stent application; injecting the optimal PLA-TEC composite into the custom mold using a microinjection molding machine, wherein the machine has a clamping capacity of 10 tons and a maximum injection pressure of 250 MPa, and wherein the injection parameters are refined based on melt-flow simulations to ensure precise filling of the stent cavity; producing the stent in a single machining process without the need for preparing separate parts, thereby ensuring the stent is formed as a complete unit; post-processing the molded stent to achieve desired specifications, including cutting and trimming as necessary; and conducting quality control checks on the final stent to ensure compliance with biocompatibility and structural integrity standards.