#polydopamine

A nature-inspired coating to keep drugs from breaking down too early

Chemists have developed a coating that could make certain medications and other materials more stable by covering them with an outer layer much thinner than the width of a human hair.

That coating secures whatever is inside, the researchers said, and could make it possible for medications to have fewer additives used to keep them from breaking apart early.

"Think about it like a row of coins—a stack of quarters—and the stack on its own will probably fall apart," said Jon Parquette, senior author of the study and a professor of chemistry at The Ohio State University. "But if you get a stack of quarters from the bank, they put a plastic coating on the stack, and that plastic coating holds all the coins together. That's exactly what we've done here."

The difference: The researchers created this coating from polydopamine, a material inspired by nature but created in a laboratory. And they used it to cover peptide nanofibers, very small chains of amino acids that are the building blocks of proteins. Peptide nanofibers are some of the building blocks of materials we use regularly, including medications, and form by a process called "self-assembly." Think of the stack of coins: Each peptide molecule is like one coin; the entire stack itself is a peptide nanofiber. The coating makes that stack impervious to environments that could cause the stack to fall.

A moldable scaffold for bone

A team including researchers at Rensselaer Polytechnic Institute is developing a new material that can be used to replace skull bone lost to injury, surgery, or birth defect. The bioactive foam is malleable when exposed to warm saline (similar to a sponge), allowing surgeons to easily shape it to fit irregular defects in the skull, where it hardens in place. Once implanted in the skull, specially coated pores within the foam attract bone cells, naturally regenerating bone to replace the foam, which dissolves over time.

The foam -- a shape memory polymer coated in a bioactive polydopamine -- is intended as an alternative to materials currently used to treat cranio-maxillofacial gaps. Most commonly, such gaps are filled with a bone graft surgically harvested from the patient, such as from the hip. Such rigid bone grafts are often difficult to harvest, and cannot be readily manipulated to fit within irregularly shaped bone defects, compromising healing.

The research is supported by a four-year $1.9 million grant from the National Institutes of Health (NIH), and is led by Texas A&M University associate professor Melissa Grunlan, who developed the foam.

"This is like trying to fill in a missing puzzle piece with the wrong piece," Grunlan said. "These bone defects can cause tremendous functional problems and aesthetic issues for individuals, so it was recognized that a better treatment would make a big impact."

The world of drug delivery is on the brink of a revolution, with innovative solutions like the Oral Colon-Specific Drug Delivery System (OCDDS) taking center stage. This system aims to precisely target drug release to the colon, avoiding premature release in the stomach and small intestine. The benefits are twofold: increasing drug concentration at the site of action while minimizing systemic side effects. Two key players in this revolution are molecular imprinting and chitosan, which are being harnessed to create intelligent polymer materials and improve treatment outcomes. This article will delve deeper into the science behind molecular imprinting, chitosan, and their applications in drug delivery, particularly for colorectal cancer treatment.

Molecular Imprinting: A Game-Changer in Drug Delivery

Molecular imprinting is a cutting-edge technology that has gained significant attention for its ability to create intelligent polymer materials with specific recognition capabilities for target molecules. These materials, known as molecularly imprinted polymers (MIPs), are synthesized by polymerizing functional monomers around a template molecule, which is then removed, leaving behind cavities that are complementary in shape, size, and chemical functionality to the template. This process endows MIPs with predetermined recognition ability, making them highly selective for the target molecule.

MIPs offer numerous advantages over traditional drug delivery systems. They are highly stable, both thermally and chemically, and can withstand harsh conditions that would degrade other materials. Additionally, MIPs are cost-effective, as they can be easily synthesized and are reusable. Their high selectivity and affinity for the target molecule enable them to effectively control drug release, making them ideal for creating high-performance drug delivery systems.

Harnessing the Power of Chitosan

Chitosan, derived from chitin, is a versatile amino-polysaccharide that has gained considerable attention in the field of drug delivery due to its biocompatibility and biodegradability. Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine and N-acetyl-D-glucosamine units. Its functional groups, such as amino and hydroxyl groups, allow for structural modifications, making it a valuable resource for preparing MIPs.

Chitosan-based MIPs offer several advantages over traditional MIPs. They are more biocompatible and biodegradable, reducing the risk of adverse reactions and long-term accumulation in the body. Additionally, chitosan's cationic nature enables it to interact with negatively charged molecules, expanding its applications in drug delivery.

Chemical modifications of chitosan, such as carboxymethylation, hydroxypropylation, and quaternization, can enhance its solubility and properties, further expanding its applications in various fields, including medicine. For instance, carboxymethyl chitosan has improved water solubility and mucoadhesive properties, making it an ideal candidate for colon-specific drug delivery.

Targeting Colorectal Cancer with 5-Fluorouracil

5-Fluorouracil (5-FU) is a potent chemotherapy drug for colorectal cancer, but its limitations include rapid metabolism and low bioavailability. To address these challenges, researchers are focusing on developing oral colon-specific delivery systems for 5-FU. By combining molecular surface imprinting with pH-sensitive and time-delayed release mechanisms, a novel delivery system is being designed to enhance the efficacy and safety of colorectal cancer treatment.

The OCDDS for 5-FU is based on the concept of exploiting the unique physiological conditions of the colon, such as its lower pH and the presence of specific enzymes, to achieve site-specific drug release. This system typically consists of an enteric coating that protects the drug from premature release in the stomach and small intestine, and a chitosan-based MIP core that selectively releases the drug in the colon.

The integration of molecular imprinting and chitosan in the OCDDS offers several advantages. The MIP core provides high selectivity and affinity for 5-FU, ensuring that the drug is released only in the colon. The chitosan matrix enhances the stability and biocompatibility of the system, while its pH-sensitive properties enable site-specific drug release. Additionally, the time-delayed release mechanism ensures that the drug is released over an extended period, maximizing its therapeutic effect while minimizing side effects.

Future Prospects: Integrating Molecular Imprinting, Chitosan, and Advanced Drug Delivery Systems

The integration of molecular imprinting, chitosan, and advanced drug delivery systems holds immense promise for revolutionizing targeted drug delivery. By leveraging these technologies, researchers aim to improve treatment outcomes, reduce side effects, and enhance patient care in the field of medicine.

Stay tuned for more updates on the groundbreaking advancements in drug delivery and personalized medicine! In the coming years, we can expect to see more innovative solutions that harness the power of molecular imprinting and chitosan to create intelligent, high-performance drug delivery systems. These developments will not only transform the way we treat diseases like colorectal cancer but also pave the way for a new era of personalized medicine.

The fusion of molecular imprinting and chitosan in drug delivery systems represents a significant leap forward in the field of medicine. By creating intelligent polymer materials that can recognize and control the release of specific drugs, researchers are developing targeted therapies that maximize efficacy while minimizing side effects. As these technologies continue to evolve, we can look forward to a future where personalized, effective treatments become the norm, ultimately improving patient care and outcomes.

. One area that has seen significant advancements in recent years is the development of biopolymer membranes for organic solvent nanofiltration (OSN). In this blog post, we'll explore the benefits of biopolymer membranes, their applications, and the potential for scalability in industrial settings.

What are Biopolymer Membranes?

Biopolymer membranes are a type of membrane made from natural polymers, such as agarose and natural rubber latex. These membranes are fabricated using interpenetrating polymer networks (IPN), which provide excellent mechanical strength and stability. The use of natural materials and water as a solvent during fabrication reduces the environmental impact of the production process.

The Benefits of Biopolymer Membranes

Biopolymer membranes offer several advantages over traditional fossil-based polymer materials. Firstly, they are biodegradable, ensuring an environmentally friendly end-of-life phase. Additionally, they demonstrate high mechanical strength, thermal stability, and resistance to fouling, making them suitable for long-term operation in harsh environments.

Applications of Biopolymer Membranes

Biopolymer membranes have a wide range of applications across various industries. In the pharmaceutical industry, they can be used for the purification of active pharmaceutical ingredients (APIs) and the removal of carcinogenic impurities. In petrochemical and biorefining applications, they can be used for the separation of molecular species in harsh organic media.

Scalability and Industrial Applications

One of the key advantages of biopolymer membranes is their scalability. The fabrication process can be easily scaled up to meet the demands of industrial applications. In fact, pilot-scale studies have shown that biopolymer membranes can be fabricated on a large scale while maintaining their performance and properties.

The Future of Sustainable Technology

The development of biopolymer membranes for OSN is a significant step towards a more sustainable future. As industries continue to adopt green solvents and sustainable technologies, the demand for biopolymer membranes is likely to increase. With their excellent performance, scalability, and biodegradability, biopolymer membranes are poised to revolutionize the field of organic solvent nanofiltration.

The increasing demand for sustainable alternatives to fossil-bas…

The increasing demand for sustainable alternatives to fossil-based polymer materials has led to the development of innovative biopolymer membranes for organic solvent nanofiltration (OSN). In a recent study, researchers have successfully fabricated interpenetrating biopolymer network (IPN) membranes from natural compounds, agarose and natural rubber latex, without the use of toxic cross-linking agents. This breakthrough technology offers a promising solution for the separation of molecular species in harsh organic media, benefiting various industries such as petrochemical, biorefining, paint, pharmaceutical, and food.

Key Features of the Biopolymer Membranes

The biopolymer membranes exhibit excellent solvent resistance and tunable molecular sieving, making them suitable for a wide range of applications. The membranes are biodegradable, ensuring an environmentally friendly end-of-life phase. The use of natural materials and water as a solvent during fabrication reduces the environmental impact of the production process. Additionally, the membranes demonstrate high mechanical strength, thermal stability, and resistance to fouling, making them suitable for long-term operation in harsh environments.

Fabrication and Characterization of the Membranes

The IPN membranes were fabricated by combining agarose and natural rubber latex through a self-assembly and self-cross-linking process. The morphology and chemical information of the membranes were characterized using various techniques, including scanning electron microscopy (SEM), atomic force microscopy (AFM), and nano-Fourier transform infrared (nano-FTIR) spectroscopy. The results revealed a textured dense microstructure with a water contact angle of 71° ± 1° and a roughness value of 138.75 nm. The membranes' surface chemistry was also analyzed using X-ray photoelectron spectroscopy (XPS), which showed a high concentration of hydroxyl and carboxyl groups, contributing to their hydrophilic nature.

Nanofiltration Performance and Biodegradability

The nanofiltration performance of the membranes was evaluated using a crossflow filtration system. The results showed a linear correlation between the pure solvent flux and the solubility parameter, indicating that the membranes can be used with optimum linear control over polar solvents. The membranes demonstrated long-term stability over 72 h of continuous crossflow nanofiltration at 20 bar. The biodegradability of the membranes was confirmed through enzymatic treatment, ensuring a sustainable end-of-life phase. The membranes' biodegradability was further evaluated using a soil burial test, which showed a significant reduction in membrane weight and molecular weight over a period of 6 months.

API Purification and Impurity Removal

The membranes were successfully used for the purification of an active pharmaceutical ingredient (API) and the removal of a carcinogenic impurity. The results showed that the membranes can effectively remove impurities below the threshold of toxicological concern, making them suitable for pharmaceutical applications. The membranes' ability to remove impurities was further evaluated using a range of analytical techniques, including high-performance liquid chromatography (HPLC) and mass spectrometry (MS).

Scalability and Industrial Applications

The scalability of the membrane fabrication process was evaluated using a pilot-scale setup. The results showed that the membranes can be fabricated on a large scale while maintaining their performance and properties. The membranes' potential for industrial applications was further evaluated through collaborations with industry partners, which showed promising results in the areas of petrochemical, biorefining, and pharmaceuticals.