http://www.mtdna.or.kr/neowiz/board/up_files/files_17/Chitin_Chitosan_polymers_chemistrySolubilityFiberFormation.pdf

Chitin and chitosan polymers: Chemistry, solubility and fiber formation

Biomaterials based on chitin and chitosan in wound dressing applications

This review describes the most common methods for recovery of chitin from marine organisms. In depth, both enzymatic and chemical treatments for the step of deproteinization are compared, as well as different conditions for demineralization. The conditions of chitosan preparation are also discussed, since they significantly impact the synthesis of chitosan with varying degree of acetylation (DA) and molecular weight (MW). In addition, the main characterization techniques applied for chitin and chitosan are recalled, pointing out the role of their solubility in relation with the chemical structure (mainly the acetyl group distribution along the backbone). Biological activities are also presented, such as: antibacterial, antifungal, antitumor and antioxidant. Interestingly, the relationship between chemical structure and biological activity is demonstrated for chitosan molecules with different DA and MW and homogeneous distribution of acetyl groups for the first time. In the end, several selected pharmaceutical and biomedical applications are presented, in which chitin and chitosan are recognized as new biomaterials taking advantage of their biocompatibility and biodegradability.

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Chitin and Chitosan Preparation from Marine Sources. Structure, Properties and Applications

New achievements in the realm of nanoscience and innovative techniques of nanomedicine have moved micro/nanoparticles (MNPs) to the point of becoming actually useful for practical applications in the near future. Various differences between the extracellular and intracellular environments of cancerous and normal cells and the particular characteristics of tumors such as physicochemical properties, neovasculature, elasticity, surface electrical charge, and pH have motivated the design and fabrication of inventive “smart” MNPs for stimulus-responsive controlled drug release. These novel MNPs can be tailored to be responsive to pH variations, redox potential, enzymatic activation, thermal gradients, magnetic fields, light, and ultrasound (US), or can even be responsive to dual or multi-combinations of different stimuli. This unparalleled capability has increased their importance as site-specific controlled drug delivery systems (DDSs) and has encouraged their rapid development in recent years. An in-depth understanding of the underlying mechanisms of these DDS approaches is expected to further contribute to this groundbreaking field of nanomedicine. Smart nanocarriers in the form of MNPs that can be triggered by internal or external stimulus are summarized and discussed in the present review, including pH-sensitive peptides and polymers, redox-responsive micelles and nanogels, thermo- or magnetic-responsive nanoparticles (NPs), mechanical- or electrical-responsive MNPs, light or ultrasound-sensitive particles, and multi-responsive MNPs including dual stimuli-sensitive nanosheets of graphene. This review highlights the recent advances of smart MNPs categorized according to their activation stimulus (physical, chemical, or biological) and looks forward to future pharmaceutical applications.

/pdf/smart-micro-nanoparticles-in-stimulus-responsive-drug-gene-1duzknz8dr.pdf

Smart micro/nanoparticles in stimulus-responsive drug/gene delivery systems

Chitins and chitosans for the repair of wounded skin, nerve, cartilage and bone

Chitin nanofibrils/chitosan glycolate composites as wound medicaments

Over the past years, lipofilling has been used for many pathologies and sequelae; recently, its use has also widened for burn outcomes. A total of 93 burn scars were assessed (from September 2011 to February 2012). Half of scar area was treated through injection of adipose tissue harvested from subcutaneous fat and processed in accordance with the Coleman technique. Biopsy specimens were taken before treatment and at 3 and 6 months after the treatment. Histologic and immunohistochemical evaluations were conducted. In the samples examined, a marked improvement was observed, which can be seen in 3 months, but most of all, documented at 6 months. In addition, from a clinical point of view, an improvement has been documented, both functional and aesthetic. Lipofilling for burn scar complete and improve the results of standard surgical procedures, with long-term care setting and long-acting results.

Burn scar lipofilling: immunohistochemical and clinical outcomes

Background
The reduction of mortality worldwide has led older individuals to seek intervention modalities to improve their appearance and reverse signs of aging.

/pdf/a-phosphatidylcholine-hyaluronic-acid-chitin-nanofibrils-2doxu1tzg3.pdf

A phosphatidylcholine hyaluronic acid chitin–nanofibrils complex for a fast skin remodeling and a rejuvenating look

Scarring after a burn injury remains the greatest unmet challenge in the treatment of functional and psychosocial sequelae of burns. The hypertrophic scar represents the most common type of cicatrix after burns, and it has a prevalence of up to 70%. We present a case of upper and lower extremity partial-thickness burns in a female patient treated in two different modalities. Superficial seconddegree burns on the upper extremities were treated with conservative dressing with fairly early wound closure but they developed hypertrophic scars. Deeper, lower extremity burns were debrided with a new bromelain-based debriding agent, resulting in scar-free healing. The pathophysiology of hypertrophic scar formation is based on the perturbation of collagen production or degradation or both. The duration and magnitude of the inflammatory phase of wound healing also appears to play a role in hypertrophic scarring. Bromelain has demonstrated an anti-angiogenic effect in various cancer cell lines and it has been shown to regulate a variety of pro-angiogenic growth factors. This case raises the classical question of the relationship between time to healing and formation of hypertrophic scars after burn injury, pointing to other potential factors that may play an important role in burn healing.

Paolo Palombo

Papers

Chitin nanofibrils/chitosan glycolate composites as wound medicaments

Burn scar lipofilling: immunohistochemical and clinical outcomes

A phosphatidylcholine hyaluronic acid chitin–nanofibrils complex for a fast skin remodeling and a rejuvenating look

Spontaneous healing and scar control following enzymatic debridement of deep second-degree burns

O27.6 The use of Versajet hydrosurgery: 5 years experience