EP-4737095-A1 - METHOD FOR PRODUCING A BIORESORBABLE AND/OR BIOCOMPATIBLE OPTICAL FIBER

EP4737095A1EP 4737095 A1EP4737095 A1EP 4737095A1EP-4737095-A1

Abstract

Method for producing a bioresorbable and/or biocompatible optical fiber, comprising at least the following steps: a) provision of at least one hydrogel of at least one polymer; said polymer of said solution being selected from the group comprising bioresorbable and/or biocompatible polymers; said hydrogel being provided with a threshold temperature, which divides: a first temperature range, above or below said threshold temperature, wherein said hydrogel is in a liquid state; a second temperature range, below or above said threshold temperature, wherein said hydrogel is in a solid state; said method comprising at least a further step: b) first temperature regulation of said hydrogel, though heating and/or cooling means, so as to heat and/or cool said hydrogel above and/or below a said threshold temperature, in order to lead said hydrogel in the first temperature range; c) extrusion of said hydrogel in liquid state through extrusion means, obtaining at least a filament of said hydrogel; during said step c) said hydrogel changing from said first temperature range to said second temperature range in solid state; said filament of said hydrogel in solid state defining an optical fiber.

Inventors

SURDO, Salvatore
Minopoli, Antonio
BELLOTTI, ELENA
BARILLARO, GIUSEPPE

Assignees

Università di Pisa

Dates

Publication Date: 20260506
Application Date: 20241029

Claims (15)

Method for producing a bioresorbable and/or biocompatible optical fiber (1), comprising at least the following steps: a) provision of at least one hydrogel (2) of at least one polymer; said polymer being selected from the group comprising bioresorbable and/or biocompatible polymers; characterized in that said hydrogel (2) being provided with a threshold temperature, which divides the possible temperatures of said hydrogel (2) in two operating temperature ranges: - a first temperature range, wherein said hydrogel (2) is in a liquid state; - a second temperature range, opposite to said first temperature range, wherein said hydrogel (2) is in a solid state; said method comprising at least the following further steps: b) first temperature regulation of said hydrogel (2), through heating and/or cooling means (3), so as to heat and/or cool said hydrogel (2) above and/or below said threshold temperature, in order to lead said hydrogel (2) in the first temperature range; c) extrusion of said hydrogel (2) in liquid state through extrusion means (4), shaping said hydrogel into at least a filament (5); during said step c) said hydrogel (2) changing from said first temperature range in liquid state to said second temperature in solid state; said filament (5) of said hydrogel (2) in solid state defining said optical fiber (1).
Method for producing a bioresorbable and/or biocompatible optical fiber according to claim 1, characterized in that said at least one polymer is selected from the group comprising Agarose, Methylcellulose, Pluronic, Polyethylene glycol diacrylate (PEGDA), Polyacrylamide (PAM) and/or their functionalized form.
Method for producing a bioresorbable and/or biocompatible optical fiber according to one or more of the preceding claims, characterized in that said polymer is Agarose.
Method for producing a bioresorbable and/or biocompatible optical fiber according to one or more of the preceding claims, characterized in that said first temperature range is above said threshold temperature and said second temperature range is below said threshold temperature.
Method for producing a bioresorbable and/or biocompatible optical fiber according to one or more of the preceding claims, characterized in that said at least one polymer is used in a concentration comprised between 1 to 3 %w/v.
Method for producing a bioresorbable and/or biocompatible optical fiber according to one or more of the preceding claims, characterized in that said at least one polymer is used in a concentration equal to 2 %w/v.
Method for producing a bioresorbable and/or biocompatible optical fiber according to one or more of the preceding claims, characterized in that said step a) comprises a first sub-step of heating said solution, preferably between 50°C and 80°C.
Method for producing a bioresorbable and/or biocompatible optical fiber according to one or more of the preceding claims, characterized in that said step a) comprises a second sub-step of stirring said solution, obtaining and homogeneous liquified hydrogel (2).
Method for producing a bioresorbable and/or biocompatible optical fiber according to one or more of the preceding claims, characterized in that said step c) involves the passage of the liquified hydrogel (2) through a nozzle (6) having a cross section equal to the cross section desired for the optical fiber (1).
Method for producing a bioresorbable and/or biocompatible optical fiber according to one or more of the preceding claims, characterized in that said nozzle (6) has a cross section having an average diameter comprised between 0.1 and 2 mm, so that said step c) provides an optical fiber (1) having an average diameter comprised between 0.1 and 2 mm.
Method for producing a bioresorbable and/or biocompatible optical fiber according to one or more of the preceding claims, characterized in that said nozzle (6) extends between a first end (7) in which, during said step c) the hydrogel (2) enters in the liquid state, and a second end (8) from which, during said step c), the hydrogel (2) exits in the solid state.
Method for producing a bioresorbable and/or biocompatible optical fiber according to one or more of the preceding claims, characterized in that , upstream of said first end (7), the hydrogel (2) is kept in said first temperature range, in said step c) said hydrogel (2) passes from the first temperature range to the second temperature range while it is extruded through said nozzle (6).
Method for producing a bioresorbable and/or biocompatible optical fiber according to one or more of the preceding claims, characterized in that said step b) is executed by housing said hydrogel (2) in a reservoir (9) heated by heating means (3), said reservoir (9) being fluidically connected to said first end (7) of said nozzle (6).
Method for producing a bioresorbable and/or biocompatible optical fiber according to claim one or more of the preceding claims, characterized in that said at least one polymer of said hydrogel is a functionalized polymer comprising at least one receptor configured to bind at least one target molecule.
Bioresorbable and/or biocompatible optical fiber (1) comprising at least one layer of hydrogel (2) of at least one polymer, said polymer being selected from the group comprising bioresorbable and/or biocompatible polymers; characterized in that said hydrogel (2) is provided with a threshold temperature, which divides the possible temperatures of said hydrogel (2) in two operating temperature ranges: - a first temperature range, wherein said hydrogel (2) is in a liquid state; - a second temperature range, opposite to said first temperature range, wherein said hydrogel (2) is in a solid state.

Description

Field of application of the invention The present invention concerns a method for producing a bioresorbable and/or biocompatible optical fiber and hence finds advantageous application in the technical field of optical devices, namely devices for the transport of light, such as optical fibers, and more specifically to a method for producing optical fibers which are biocompatible and/or bioresorbable. The method according to the present invention permits to prepare optical fibers intended to be used in human bodies, for treating diseases or collect information for diagnostic purposes. Another aspect of the present invention concerns also a method for functionalizing a polymer, which can be implemented in the above-mentioned method for producing a bioresorbable and/or biocompatible optical fiber. Therefore, the present invention finds application in the technical field of producing and commercialising medical equipment and devices. More specifically, the present invention finds advantageous use in the technical field of the production and marketing of sensors, apparatus or other devices for the therapeutic and/or diagnostic/sensing applications. State of the art The use of optical fibers for therapeutic and/or diagnostic/sensing applications purposes has been known for a long time. More specifically, biocompatible optical fibers, which are intended for use in medical and biomedical applications without causing tissue damage or provoking adverse reactions in the human or animal body, have been raised great interest. Optical fibers are widely used in various medical applications, particularly in human therapeutic purposes, due to their unique properties of transmitting light with minimal loss over long distances. For example, optical fibers are used in endoscopes for minimally invasive surgery, allowing for real-time imaging and light delivery. Recent advancements have improved the flexibility, durability, and miniaturization of these fibers, enabling better access to difficult-to-reach areas within the body. Moreover, optical fibers are used to deliver light to activate photosensitive drugs in photodynamic therapy, a treatment for cancer and other pathological conditions. The latest fibers are designed to precisely control light delivery, minimizing damage to surrounding healthy tissues. In treatments such as hyperthermia for cancer, optical fibers are used to measure and deliver heat to tissues. State-of-the-art fibers offer real-time temperature monitoring and control, ensuring therapeutic levels are reached without overheating surrounding tissues. Nowadays, research is ongoing into developing biocompatible and even biodegradable optical fibers that can be safely left in the body after delivering therapy, eliminating the need for removal surgery. For example, optical fibers known in the state of the art are used for irradiating a specific molecule with light in a specific range of wavelengths and then measuring the concentration of the latter (e.g. oxygen, glucose, etc.), by knowing its characteristic absorption spectrum in the aforementioned range of wavelengths. Optical fibers are suited to assess the activity of several types of cells, such as neurons, by providing light stimuli. For example, optical fibers are already known in the field of photodynamic phototherapy (also known as PDT) since they are suited to extend the PDT to the treatment of tumours located in deep tissues. This type of biocompatible optical fibers is designed to combine the light transmission properties intrinsic to the traditional optical fibers with coating material that is safe when contacting biological tissue. However, biocompatible optical fibers must be surgically removed after their utilization as they cannot be reabsorbed by the patient's body. Recently, there has seen significant progress in the development and realization of optical fibers made of materials that are not only biocompatible but also bioabsorbable, i.e. they can be reabsorbed by the body after performing their function, eliminating the need for a second operation to remove the fibers itself. The known methods for producing above-mentioned optical fibers generally provide the use of biocompatible and bioresorbable materials, such as polymers, glass or proteins. However, the methods already known in the state of the art for producing biocompatible and bioresorbable optical fibers are particularly complex to implement. Another drawback is that the above-mentioned methods require the execution of multiple steps in order to produce a biocompatible and/or bioresorbable optical fiber. Another drawback of the above-mentioned method is that it requires the use of chemical solvents and/or reagents that are toxic and/or cytotoxic for the human body and/or for any biological tissue. Therefore, another drawback of the prior art methods relies in that the optical fiber thus produced can have traces of toxic and/or cytotoxic solvent, which render them detrimental for biologic