Platelet rich fibrin and simvastatin-loaded pectin-based 3D printed-electrospun bilayer scaffold for skin tissue regeneration.

Designing multifunctional wound dressings is a prerequisite to prevent infection and stimulate healing. In this study, a bilayer scaffold (BS) with a top layer (TL) comprising 3D printed pectin/polyacrylic acid/platelet rich fibrin hydrogel (Pec/PAA/PRF) and a bottom nanofibrous layer (NL) containing Pec/PAA/simvastatin (SIM) was produced. The biodegradable and biocompatible polymers Pec and PAA were cross-linked to form hydrogels via Ca2+ activation through galacturonate linkage and chelation, respectively. PRF as an autologous growth factor (GF) source and SIM together augmented angiogenesis and neovascularization. Because of 3D printing, the BS possessed a uniform distribution of PRF in TL and an average fiber diameter of 96.71 ± 18.14 nm was obtained in NL. The Young's modulus of BS was recorded as 6.02 ± 0.31 MPa and its elongation at break was measured as 30.16 ± 2.70 %. The wound dressing gradually released growth factors over 7 days of investigation. Furthermore, the BS significantly outperformed other groups in increasing cell viability and in vivo wound closure rate (95.80 ± 3.47 % after 14 days). Wounds covered with BS healed faster with more collagen deposition and re-epithelialization. The results demonstrate that the BS can be a potential remedy for skin tissue regeneration.

A double-layer cellulose/pectin-soy protein isolate-pomegranate peel extract micro/nanofiber dressing for acceleration of wound healing.

Multi-layered wound dressings can closely mimic the hierarchical structure of the skin. Herein, a double-layer dressing material is fabricated through electrospinning, comprised of a nanofibrous structure as a healing-support layer or the bottom layer (BL) containing pectin (Pec), soy protein isolate (SPI), pomegranate peel extract (P), and a cellulose (Cel) microfiber layer as a protective/monitoring layer or top layer (TL). The formation of a fine bilayer structure was confirmed using scanning electron microscopy. Cel/Pec-SPI-P dressing showed a 60.05 % weight loss during 7 days of immersion in phosphate buffered solution. The ultimate tensile strength, elastic modulus, and elongation at break for different dressings were within the range of 3.14-3.57 MPa, 32.26-36.58 MPa, and 59.04-63.19 %, respectively. The release of SPI and phenolic compounds from dressings were measured and their antibacterial activity was evaluated. The fabricated dressing was non-cytotoxic following exposure to human keratinocyte cells. The Cel/Pec-SPI-P dressing exhibited excellent cell adhesion and migration as well as angiogenesis. More importantly, in vivo experiments on Cel/Pec-SPI-P dressings showed faster epidermal layer formation, blood vessel generation, collagen deposition, and a faster wound healing rate. Overall, it is anticipated that the Cel/Pec-SPI-P bilayer dressing facilitates wound treatment and can be a promising approach for clinical use.

Angiogenesis, hemocompatibility and bactericidal effect of bioactive natural polymer-based bilayer adhesive skin substitute for infected burned wound healing.

Thermal wounds are complex and lethal with irregular shapes, risk of infection, slow healing, and large surface area. The mortality rate in patients with infected burns is twice that of non-infected burns. Developing multifunctional skin substitutes to augment the healing rate of infected burns is vital. Herein, we 3D printed a hydrogel scaffold comprising carboxymethyl chitosan (CMCs) and oxidized alginate grafted catechol (O-AlgCat) on a hydrophobic electrospun layer, forming a bilayer skin substitute (BSS). The functional layer (FL) was fabricated by physiochemical crosslinking to ensure favorable biodegradability. The gallium-containing hydrophobic electrospun layer or backing layer (BL) could mimic the epidermis of skin, avoiding fluid penetration and offering antibacterial activity. 3D printed FL contains catechol, gallium, and biologically active platelet rich fibrin (PRF) to adhere to both tissue and BL, show antibacterial activity, encourage angiogenesis, cell growth, and migration. The fabricated bioactive BSS exhibited noticeable adhesive properties (P ≤ 0.05), significant antibacterial activity (P ≤ 0.05), faster clot formation, and the potential to promote proliferation (P ≤ 0.05) and migration (P ≤ 0.05) of L929 cells. Furthermore, the angiogenesis was significantly higher (P ≤ 0.05) when evaluated in vivo and in ovo. The BSS-covered wounds healed faster due to low inflammation and high collagen density. Based on the obtained results, the fabricated bioactive BSS could be an effective treatment for infected burn wounds.

A poly-l-lysine-bonded TEMPO-oxidized bacterial nanocellulose-based antibacterial dressing for infected wound treatment.

Oxidized bacterial nanocellulose (O-BNC) is a favorable material to subdue bacterial infection because of the carboxylate content that not only has a weak antibacterial activity but also is capable of bonding electrostatically to polycationic antibacterial agents. In this study, the 2,2,6,6-Tetramethylpiperidinyloxy radical (TEMPO)-mediated oxidation of BNC was optimized to achieve high carboxylate content while retaining an acceptable tensile profile. To develop an O-BNC-based functional wound dressing, ε-poly-l-lysine (PLL) was then covalently bonded with O-BNC via 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) reaction after homogeneous distribution by ultrasonication. The antibacterial activity of the obtained wound dressing was significantly higher (p < 0.05), and no toxicity was observed. The infected full-thickness wounds of rats were healed faster (p < 0.05) covered by the dressing due to less inflammation, faster blood vessel proliferation, and epidermal layer formation. The material is an effective and promising functional dressing for the treatment of infected wounds.

Assessment of biosafety implementation in clinical diagnostic laboratories in Pakistan during the COVID-19 pandemic.

Laboratory diagnostic capacity is crucial for an optimal national response to a public health emergency such as the COVID-19 pandemic. Preventing laboratory-acquired infections and the loss of critical human resources, especially during a public health emergency, requires laboratories to have a good biorisk management system in place. In this study, we aimed to evaluate laboratory biosafety and biosecurity in Pakistan during the COVID-19 pandemic. In this cross-sectional study, a self-rated anonymous questionnaire was distributed to laboratory professionals (LPs) working in clinical diagnostic laboratories, including laboratories performing polymerase chain reaction (PCR)-based COVID-19 diagnostic testing in Punjab, Sindh, Khyber Pakhtunkhwa, and Gilgit-Baltistan provinces as well as Islamabad during March 2020 to April 2020. The questionnaire assessed knowledge and perceptions of LPs, resource availability, and commitment by top management in these laboratories. In total, 58.6% of LPs performing COVID-19 testing reported that their laboratory did not conduct a biorisk assessment before starting COVID-19 testing in their facility. Only 31% of LPs were aware that COVID-19 testing could be performed at a biosafety level 2 laboratory, as per the World Health Organization interim biosafety guidelines. A sufficiently high percentage of LPs did not feel confident in their ability to handle COVID-19 samples (32.8%), spills (43.1%), or other accidents (32.8%). These findings demonstrate the need for effective biosafety program implementation, proper training, and establishing competency assessment methods. These findings also suggested that identifying and addressing gaps in existing biorisk management systems through sustainable interventions and preparing LPs for surge capacity is crucial to better address public health emergencies.