Hydrophilic medical coatings have contributed to improving the safety and function of many biomedical devices. These coatings provide many functions, such as reduced friction, biocompatibility, thromboresistance, and more. One of the critical materials used by companies like Hydromer®, Inc. for hydrophilic medical coatings is chitosan. Chitosan-based hydrophilic coatings possess excellent properties. They are non-toxic to the body, can degrade naturally, and can inhibit microbial growth. Due to these properties, chitosan coatings are ideal for a wide range of medical applications. These include medical devices, wound dressings, surgical implants, and drug delivery systems.
This article discusses how medical grade chitosan is being used to advance the effectiveness of hydrophilic medical coatings. We also dive into what’s on the horizon for its use in medicine. Lastly, we look at Hydromer’s innovative chitosan based offerings.
Related: Hydrophilic Coatings for Medical Devices
Introduction to Chitosan
Chitosan is a natural substance made from chitin. Chitin is found in the shells of sea creatures like shrimp and crabs, as well as in some fungi. Chitosan is created by treating chitin with an alkaline solution, which removes certain chemical groups.
Structure of Chitosan
Chitosan is made up of two main types of sugar units: D-glucosamine and N-acetyl-D-glucosamine. These sugar units are connected in a specific way, which affects how well chitosan dissolves in water and its various uses.
Extraction of Chitosan From Shells
As mentioned earlier, chitosan is extracted from the shells of crustaceans. This is done by using a multi-step chemical extraction process. Other methods, such as biological methods, are also being explored, but are not as common.
The creation of chitin (and ultimately chitosan) uses readily-available, waste materials from the seafood industry. In a way, the use of this material helps to reduce waste, which would otherwise go to landfills.
Factors Affecting Chitosan Production
The amount and quality of chitosan produced can change. This is driven by the type of crustacean used and the methods applied during extraction. For example, the type and concentration of acids or bases used can greatly impact the final product.
Understanding these factors is important for developing chitosan as a valuable biopolymer with many potential applications.
Medical Grade Chitosan
It is important to note that not all chitosan is suitable for medical use, including chitosan-based medical coatings. Medical grade chitosan is manufactured to meet GMP requirements and strict regulatory standards. The material undergoes more processing steps to ensure it meets requirements.
Chitosan Properties Relevant to Medical Coatings
Chitosan is a highly hydrophilic (water-loving), bioadhesive, and antimicrobial material. It’s properties make it highly suitable for use in hydrophilic medical coatings.
Some key properties of Chitosan include:
- Biocompatibility – Chitosan-based coatings are safe for human tissues and do not cause toxic reactions.
- Biodegradability – It naturally breaks down into non-toxic byproducts
- Antibacterial/Antimicrobial Activity – Inhibits the growth of pathogens, reducing the risk of infections.
- Film-Forming Ability – Can be easily processed into thin coatings for use on a wide range of medical applications.
- Moisture Retention – Chitosan medical coatings help maintain a hydrated environment, beneficial for wound healing as well as lubrication.
The Role of Chitosan in Hydrophilic Coatings
Hydrophilic coatings are essential for reducing surface friction in medical devices such as catheters and stents. Chitosan is a key material in the creation of these coatings.
Chitosan Enhances Hydrophilicity
The material is commonly used for hydrophilic coatings, including medical coatings. This is due to its ability to enhance hydrophilicity in the following ways:
- Forming hydrogen bonds with water molecules, creating a moisture-retaining layer
- Increasing surface wettability, which enhances lubrication properties
- Allowing controlled swelling, making it useful for drug delivery applications
Reduction of Friction and Improved Performance
Medical devices that are inserted into the body, like catheters and guidewires, need to have surfaces with very low friction. This lubricity helps prevent discomfort for patients as well as damage to their tissues.
One effective way to achieve this is by using chitosan or other hydrophilic coatings. These “slippery-when-wet” coatings create a slick layer on the medical device in the presence of moisture. This slippery layer makes it easier for devices to move within the body. It also reduces the chance of injury and trauma.
Chitosan vs Conventional Coating Materials
Hydrophilic coatings are also made with polymers like polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG). But other polymers often cannot fight bacteria. On the other hand, chitosan not only improves water attraction (hydrophilicity) but it also has natural antibacterial properties. This makes chitosan a better choice in some cases compared to other medical coatings.
Biomedical Applications and Benefits of Chitosan-Based Hydrophilic Coatings
Below we discuss some of the most common uses of chitosan based hydrophilic medical device coatings.
- Catheters and Stents
- Chitosan-coated urinary and vascular catheters exhibit reduced bacterial adhesion. These coatings help minimize the risk of catheter-associated infections (CAUTIs).1
- Cardiovascular stents coated with chitosan coatings show improved biocompatibility. They have reduced thrombosis risks and enhanced endothelial cell attachment.2
- Learn more about hydrophilic catheter coatings
- Wound Dressings and Bandages
- Hydrophilic chitosan coatings improve moisture retention, helping to accelerate wound healing.3
- Antimicrobial properties prevent infections in chronic wounds and burns.4,5
- Bioactive wound dressings infused with chitosan support fibroblast proliferation, essential for tissue regeneration.6
- Surgical Implants and Prosthetics
- Chitosan coatings on orthopedic implants reduce bacterial colonization. This helps to reduce the risk of post-surgical infections.7
- Chitosan can be used for biodegradable coatings. These allow gradual degradation, reducing the need for implant removal surgeries.8
- Dental implants benefit from chitosan’s bioadhesive nature. They promote better tissue integration.9
- Chitosan-based coatings for dental implants also prevent biofilm formation, reducing gum disease risks.9
- Drug Delivery Systems
- Chitosan-based microparticles and nanoparticles serve as controlled-release carriers.10
- Smart hydrogels can incorporate chitosan for responsive drug release.
- Hydrophilic coatings based on chitosan enhance drug solubility and bioavailability. This is especially true for poor water-soluble drugs.
- Transdermal patches using chitosan help improve drug penetration through the skin.11
- Ophthalmic Applications
- Contact lenses coated with chitosan retain moisture, providing enhanced comfort for dry-eye patients.12
- Ophthalmic drug delivery systems utilizing chitosan improve drug residence time and absorption.13
Chitosan Market Trends and Commercialization
There is increasing demand for biodegradable and biocompatible medical coatings. There is also growth in minimally invasive medical devices, driving the need for lubricious coatings. Lastly, there is an ever-expanding list of applications in regenerative medicine and tissue engineering.
All of these factors have led to significant growth in demand for chitosan medical coatings. In fact, it is expected to see a substantial growth rate of 21.2% through 2032. It is safe to say the use of medical grade chitosan is on the rise.
Hydromer’s Use of Chitosan in Hydrophilic Coatings and Hydrogels
Hydromer®, Inc. is a manufacturer of medical coatings that are both hydrophilic (water-attracting) and biocompatible. Hydromer actively uses chitosan and its derivatives for our custom, hydrophilic coatings and hydrogels. Our chitosan based products offer medical device manufacturers many benefits for their products. These include high wettability, low friction, biocompatibility, and high performing antibacterial properties. Because of these useful features, chitosan-based coatings are perfect for medical devices like catheters, guidewires, and more.
We incorporate chitosan derivatives into our Hydromer Hydrogels, which have many benefits. In the medical world, these hydrogels are used for various purposes, such as:
- Wound care
- Burn treatment
- Drug and gene delivery
- Bio-adhesives
- Bio-electrodes
- Dental materials
- Tissue engineering implants
- Animal/Veterinary Health
- And more
Hydromer is not just a medical coatings manufacturer. What sets us apart from other coating companies is the range of support services we offer to our customers. Regardless what stage of the product development lifecycle you are in we can assist you. From contract R&D and custom formulation to contract coating services and regulatory consulting we have you covered.
Conclusion
Chitosan-based hydrophilic medical coatings are an important development in the healthcare industry. Chitosan is a natural substance that is safe for the body, fights germs, and helps retain moisture. This makes it a great choice for improving the performance of medical devices when used for medical coatings. Its use can lead to better outcomes for patients and fewer complications.
Hydromer is working hard to create better, higher performing chitosan medical coatings. As more people look for safe and biodegradable medical materials, chitosan is proving to be a flexible and eco-friendly option. With ongoing innovations, chitosan just may become a top choice for hydrophilic medical coatings.
References
Click to see references for this article.
1. Obaid NA, Alzahrani AM, Alaryni BA, et al. Effectiveness of Chitosan Coating Catheter in Preventing Catheter-Associated Urinary Tract Infection (CAUTI).
2. Meng S, Liu Z, Shen L, et al. The effect of a layer-by-layer chitosan–heparin coating on the endothelialization and coagulation properties of a coronary stent system. Biomaterials. 2009;30(12):2276-2283.
3. Che X, Zhao T, Hu J, et al. Application of chitosan-based hydrogel in promoting wound healing: a review. Polymers. 2024;16(3):344.
4. Wang X, Song R, Johnson M, et al. An Injectable Chitosan-Based Self-Healable Hydrogel System as an Antibacterial Wound Dressing. Materials (Basel, Switzerland). Oct 11 2021;14(20)doi:10.3390/ma14205956
5. Ren H, Zhang Z, Lu K, Shen Y, He C, Chen X. Injectable chitosan hydrogels loaded with antioxidant agent as first-aid dressings for second-degree burn wounds. Science China Technological Sciences. 2024/03/01 2024;67(3):891-901. doi:10.1007/s11431-023-2509-4
6. Do NHN, Truong QT, Le PK, Ha AC. Recent developments in chitosan hydrogels carrying natural bioactive compounds. Carbohydrate Polymers. 2022;294:119726.
7. Bohara S, Suthakorn J. Surface coating of orthopedic implant to enhance the osseointegration and reduction of bacterial colonization: a review. Biomaterials Research. 2022/06/20 2022;26(1):26. doi:10.1186/s40824-022-00269-3
8. Amini AR, Wallace JS, Nukavarapu SP. Short-term and long-term effects of orthopedic biodegradable implants. Journal of long-term effects of medical implants. 2011;21(2):93-122. doi:10.1615/jlongtermeffmedimplants.v21.i2.10
9. Hallmann L, Gerngroß M-D. Chitosan and its application in dental implantology. Journal of Stomatology, Oral and Maxillofacial Surgery. 2022/11/01/ 2022;123(6):e701-e707. doi:https://doi.org/10.1016/j.jormas.2022.02.006
10. Haider A, Khan S, Iqbal DN, et al. Advances in chitosan-based drug delivery systems: A comprehensive review for therapeutic applications. European Polymer Journal. 2024/04/24/ 2024;210:112983. doi:https://doi.org/10.1016/j.eurpolymj.2024.112983
11. Ma J, Wang Y, Lu R. Mechanism and Application of Chitosan and Its Derivatives in Promoting Permeation in Transdermal Drug Delivery Systems: A Review. Pharmaceuticals (Basel, Switzerland). Apr 10 2022;15(4)doi:10.3390/ph15040459
12. Xin-Yuan S, Tian-Wei T. New contact lens based on chitosan/gelatin composites. Journal of Bioactive and Compatible Polymers. 2004;19(6):467-479.
13. Silva D, Pinto LFV, Bozukova D, Santos LF, Serro AP, Saramago B. Chitosan/alginate based multilayers to control drug release from ophthalmic lens. Colloids and Surfaces B: Biointerfaces. 2016/11/01/ 2016;147:81-89. doi:https://doi.org/10.1016/j.colsurfb.2016.07.047
