Human Wound Research Articles

Safety and effectiveness of an antiseptic wound cleansing and irrigation solution containing polyhexamethylene biguanide.

There is currently a wide range of cleansing and irrigation solutions available for wounds, many of which contain antimicrobial agents. The aim of this study was to assess the safety of HydroClean Solution (HARTMANN, Germany), a polyhexamethylene biguanide (PHMB)-containing irrigation solution, in a standard cytotoxicity assay, and to assess its effect in a three-dimensional (3D) full-thickness model of human skin. A number of commercially available wound cleansing and irrigation solutions, including the PHMB-containing irrigation solution, were tested in a cytotoxicity assay using L929 mouse fibroblasts (ISO 10993-5:2009). The PHMB-containing irrigation solution was then assessed in an in vitro human keratinocyte-fibroblast 3D full-thickness wounded skin model to determine its effect on wound healing over six days. The effect of the PHMB-containing irrigation solution on tissue viability was measured using a lactate dehydrogenase (LDH) assay, and proinflammatory effects were measured using an interleukin-6 (IL-6) production assay. The PHMB-containing irrigation solution was shown to be equivalent to other commercially available cleansing and irrigation solutions when tested in the L929 fibroblast cytotoxicity assay. When assessed in the in vitro 3D human full-thickness wound healing model, the PHMB-containing irrigation solution treatment resulted in no difference in levels of LDH or IL-6 when compared with levels produced in control Dulbecco's phosphate-buffered saline cultures. There was, however, a pronounced tissue thickening of the skin model in the periwound region. The experimental data presented in this study support the conclusion that the PHMB-containing irrigation solution has a safety profile similar to other commercially available cleansing and irrigation solutions. Evidence also suggests that the PHMB-containing irrigation solution does not affect tissue viability or proinflammatory cytokine production, as evidenced by LDH levels or the production of IL-6 in a 3D human full-thickness wound healing model. The PHMB-containing irrigation solution stimulated new tissue growth in the periwound region of the skin model.

Active self-treatment of a facial wound with a biologically active plant by a male Sumatran orangutan

Although self-medication in non-human animals is often difficult to document systematically due to the difficulty of predicting its occurrence, there is widespread evidence of such behaviors as whole leaf swallowing, bitter pith chewing, and fur rubbing in African great apes, orangutans, white handed gibbons, and several other species of monkeys in Africa, Central and South America and Madagascar. To the best of our knowledge, there is only one report of active wound treatment in non-human animals, namely in chimpanzees. We observed a male Sumatran orangutan (Pongo abelii) who sustained a facial wound. Three days after the injury he selectively ripped off leaves of a liana with the common name Akar Kuning (Fibraurea tinctoria), chewed on them, and then repeatedly applied the resulting juice onto the facial wound. As a last step, he fully covered the wound with the chewed leaves. Found in tropical forests of Southeast Asia, this and related liana species are known for their analgesic, antipyretic, and diuretic effects and are used in traditional medicine to treat various diseases, such as dysentery, diabetes, and malaria. Previous analyses of plant chemical compounds show the presence of furanoditerpenoids and protoberberine alkaloids, which are known to have antibacterial, anti-inflammatory, anti-fungal, antioxidant, and other biological activities of relevance to wound healing. This possibly innovative behavior presents the first systematically documented case of active wound treatment with a plant species know to contain biologically active substances by a wild animal and provides new insights into the origins of human wound care.

Abstract 1101: Tnfa-setdb2 Pathway Regulates Fibroblast To Myofibroblast Transition In Wound Repair

Effective healing following tissue injury is predicated on an intimate coordination between immune cells and structural cells, where recruited immune cells induce or repress structural cell proliferation and gene expression. Early after tissue injury, fibroblasts begin to transition to myofibroblasts to contract and close wounds. In pathologic conditions where wounds fail to heal (such as diabetes), fibroblasts do not increase myofibroblast gene expression; however the mechanisms that control this fibroblast transition, in normal or diabetic conditions are not defined. Our group has previously identified that epigenetic alterations can control these phenotypic switches in immune and structural cells. Here, using human wound scSeq and murine transgenic models, we examined the mechanisms that may regulate this transition in the setting of injury. First, we identified that dermal fibroblasts when treated with the pro-inflammatory cytokine TNFa, significantly repressed myofibroblast genes including acta2, tgln, myl9, cald1, fibronectin and periostin. To identify possible the epigenetic mechanisms downstream of TNFa that modulate fibroblast phenotype, we performed an unbiased epigenetic superarray on TNFa-stimulated dermal fibroblasts, where SETDB2 was significantly upregulated and was also confirmed by qPCR. SiRNA-mediated knockdown of Setdb2 in murine fibroblasts prevented TNFa-mediated repression of myofibroblast genes, suggesting regulation of this transition by Setdb2. Human scSeq identified increased Setdb2 associated with increased TNFa signaling in wound fibroblasts, suggesting an interaction of these pathways. Interestingly, we found increased TNFa in macrophages and SETDB2 in fibroblasts from human diabetic wound scSeq and a murine diabetic (DIO) model, suggesting this pathway may contribute to the decreased conversion of fibroblasts to myofibroblasts seen in non-healing diabetic wounds. This work identifies setdb2 as a TNFa-mediated regulator of fibroblast to myofibroblast transition in wound repair and may identify a new therapeutic target for impaired tissue regeneration.

Abstract 2140: The Tgfb-Whsc1 Axis Drives Macrophage To Myofibroblast Transition During Wound Repair

During the proliferative phase of tissue repair macrophages can transition to myofibroblasts, which promote wound contraction and closure. The mechanisms that control this transition remain unknown and are not well studied. Here, using a combination of murine transgenic models of disease, loss of function approaches, pharmacologic inhibition in vivo, and single cell RNA sequencing (scRNA-seq) in human wounds, we identified that a histone methyltransferase, Whsc1, regulates the fibrotic gene program in macrophages during wound repair. Specifically, we identified that Whsc1 was upregulated in wound macrophages (CD3 - CD19 - NK1.1 - Ly6G - CD11b + ) in response to TGFβ. Genetic loss of TGFβ-mediated signaling as well as siRNA knockdown of Whsc1 in bone marrow derived macrophages (BMDMs) decreased TGFβ-dependent expression of Acta2, Col1a1, Col3a1 (p<0.05). Further, TGFβ stimulation resulted in increased Whsc1 and H3K36 dimethylation at fibrotic gene promoters in wound macrophages (p<0.05). Importantly, local pharmacologic inhibition of Whsc1 in vivo significantly impaired wound healing, suggesting that Whsc1 is critical for normal wound repair. We next examined the role of Whsc1 in pathologic healing conditions (i.e. diabetes) where the macrophage-myofibroblast transition is impaired. Whsc1 expression was decreased in human macrophages analyzed by scRNA-seq of diabetic wounds and in murine wound macrophages from a diabetic model (DIO) (p<0.05). Interestingly, in DIO BMDMs, Whsc1 did not traffic to fibrotic promoters after TGFβ treatment, but rather remained at NFkB-regulated inflammatory gene promoters ( Il1b, Il6, Tnf ). On further examination of this, using co-immunoprecipitation and proximity ligation assay in BMDMs, we demonstrated increased physical interaction between RelA and Whsc1 in diabetic macrophages. Knockdown of RelA in DIO macrophages increased Whsc1 enrichment at fibrotic promoters, suggesting RelA sequestered Whsc1 at inflammatory gene promoters (p<0.05). The identification of TGFβ-Whsc1 as a driver of macrophage-myofibroblast transition in normal and pathological tissues allows for development of novel therapies to improve tissue repair, and targeting RelA in macrophages may improve diabetic wound healing.

TGFb-JMJD3 pathway regulates fibroblast to myofibroblast transition in wound repair

Abstract In normal wound healing, resident fibroblasts transition to myofibroblasts, which function to contract and close wounds. In pathologic conditions where wounds fail to heal (such as diabetes), fibroblasts do not increase myofibroblast gene expression; this mechanism is poorly understood. Using human wound scSeq and murine transgenic models, we examined the epigenetic mechanisms that may regulate this transition in the setting of injury. First, we identify that the cytokine TGFb increases myofibroblast genes in vitro. We performed an epigenetic superarray on TGFb-stimulated dermal fibroblasts, where JMJD3, an H3K27 demethylase, was significantly upregulated and was also confirmed by qPCR. ScSeq of human wounds identified JMJD3 as strongly upregulated in myofibroblasts. ChIP identified decreased H3K27me3, the activating mark of JMJD3 at myofibroblast genes further confirming its role in regulating myofibroblast genes. SiRNA knockdown of JMJD3 led to reduced myofibroblast gene expression. These findings were confirmed in a novel, tamoxifen induced, fibroblast specific knockout of JMJD3 unique to our lab. An unbaised superarray focused on remodelling and cell adhesion pathways identified that these mice have deficient levels of many structural and remodelling genes. Murine wounds were found to upregulate JMJD3 compared to distant skin, which was less pronounced in diabetic wounds. This work identifies JMJD3 as a TGFb-mediated regulator of fibroblast to myofibroblast transition.

High-Intensity Blue Light (450-460 nm) Phototherapy for Pseudomonas aeruginosa-Infected Wounds.

Background: Nosocomial wound infection with Pseudomonas aeruginosa (PA) is a serious complication often responsible for the septic mortality of burn patients. Objective: High-intensity antimicrobial blue light (aBL) treatment may represent an alternative therapy for PA infections and will be investigated in this study. Methods: Antibacterial effects of a light-emitting diode array (450-460 nm; 300 mW/cm2; 15/30 min; 270/540 J/cm2) against PA were determined by suspension assay, biofilm assay, and a human skin wound model and compared with 15-min topically applied 3% citric acid (CA) and wound irrigation solution (Prontosan®; PRT). Results: aBL reduced the bacterial number [2.51-3.56 log10 colony-forming unit (CFU)/mL], whereas PRT or CA treatment achieved a 4.64 or 6.60 log10 CFU/mL reduction in suspension assays. aBL reduced biofilm formation by 60-66%. PRT or CA treatment showed reductions by 25% or 13%. Here, aBL reduced bacterial number in biofilms (1.30-1.64 log10 CFU), but to a lower extend than PRT (2.41 log10 CFU) or CA (2.48 log10 CFU). In the wound skin model, aBL (2.21-2.33 log10 CFU) showed a bacterial reduction of the same magnitude as PRT (2.26 log10 CFU) and CA (2.30 log10 CFU). Conclusions: aBL showed a significant antibacterial efficacy against PA and biofilm formation in a short time. However, a clinical application of aBL in wound therapy requires effective active skin cooling and eye protection, which in turn may limit clinical implementation.

IL-17A-mediated JMJD3 regulation of Cxcl1 gene expression in diabetic keratinocytes increases neutrophil recruitment and impairs wound repair.

Abstract Diabetic keratinocytes display an overexpression of chemokines that contribute to prolonged inflammation and non-healing. Using sequencing, we identified that Th17 cells and an IL-17A signature predominate in human diabetic wound tissue compared to non-diabetic controls. The effects of increased IL-17A in diabetic skin on keratinocyte function is unknown. We subjected isolated murine keratinocytes to a 5hr rIL-17A stimulation and performed bulk RNA-seq. We observed increased neutrophil chemoattract genes Cxcl1, Cxcl3, Cxcl5 compared to their controls. We analyzed epigenetic enzymes known to increase gene expression and identified that JMJD3, an activating demethylase, was increased both in human and murine diabetic keratinocytes. IL-17A stimulation increased Jmjd3 expression in murine keratinocytes, and keratinocytes from mice with a keratinocyte-specific IL-17RA deficiency were unable to increase Jmjd3 with rIL-17A. Treatment with a JMJD3-specific inhibitor decreased chemokine genes in IL-17A-stimulated keratinocytes. Keratinocytes from mice with a keratinocyte-specific JMJD3-deficiency displayed decreased chemokines compared to their littermate controls with rIL-17A, suggesting that JMJD3 is relevant to IL-17A-mediated regulation of chemokines. We then analyzed immune cells recruited to the wounds of normal and diabetic mice via flow cytometry and found that Ly6G+ neutrophils were significantly increased in diabetic mice on day 5, a timepoint at which IL-17A is elevated.

Interactions between Aeromonas caviae and Yersinia enterocolitica isolated from a case of diarrhea: evaluation of antimicrobial susceptibility and immune response of infected macrophages.

Aeromonas species cause a wide spectrum of human diseases, primarily gastroenteritis, septicemia, and wound infections. Several studies have shown that about 40% of these cases involve mixed or polymicrobial infections between Aeromonas spp. and bacteria from other genera. However, the immune response of macrophages in front of the bacteria present in the mixed infections, as well as their impact on antimicrobial therapy, have not been investigated. This study evaluated the cell damage and immune response of the mouse macrophage BALB/c cell line (J774A.1) after performing a single and a mixed infection with a strain of Aeromonas caviae and Yersinia enterocolitica, both recovered from the same fecal sample from a patient with diarrhea. Macrophage cell damage was measured by the release of lactate dehydrogenase (LDH) while the immune response was evaluated studying the expression by RT-qPCR of six relevant immune-related genes. Additionally, the antimicrobial susceptibility pattern of the single and mixed strains in front of seventeen antibiotics was evaluated to determine the potential impact on the infection treatment. Macrophages infected with the mixture of the two strains showed a higher cell damage in comparison with the single infections and the immune-related genes, i.e., cytokines and chemokines genes (TNF-α, CCL20), and apoptotic and pyroptotic genes (TP53 and IL-1β) were overexpressed. After infection with the mixed cultures, an increase in the antimicrobial resistance was observed for ciprofloxacin, trimethoprim, chloramphenicol, gentamicin and ertapenem. This study increased the knowledge about the synergetic effect of the bacteria involved in mixed infection and on their potential impact on the treatment and evolution of the infection.

The Use of Fish Skin Grafts in Children as a New Treatment of Deep Dermal Burns-Case Series with Follow-Up after 2 Years and Measurement of Elasticity as an Objective Scar Evaluation.

Background: Wound healing in deep dermal burn injuries continues to be a challenge in paediatrics. In the absence quick and spontaneous wound closure, split-thickness skin grafting is often necessary. Since the development of a new type of acellular fish matrix, which is very similar to the human skin matrix, skin closure and wound conditioning can be achieved without split-thickness skin grafting. Methods: The following study shows a case series of 20 children in whom a fish skin graft was used. The aim was to develop an algorithm for selecting and using fish skin and its long-term results after one and two years. Acellular fish skin worked as a granulation base for wound healing and also as a substitute for split-thickness skin grafts. Results: There was no evidence of infection. Skin transplants and, thus, additional operations could be avoided. The follow-up examinations showed an excellent result, both objectively by means of elasticity measurements (DermalabCombo®) and in the subjective assessment of the skin as part of the Patient and Observer Scar Assessment Scale (POSAS). Conclusion: Fish skin grafts are a good alternative to split-thickness skin grafts for deep dermal wounds. These results should be further analysed with a larger number of patients in future publications.

811 The Cytotoxic Effect of CHG, Dial, and Johnson & Johnson on Human Burn Wounds

811 The Cytotoxic Effect of CHG, Dial, and Johnson & Johnson on Human Burn Wounds

A multifunctional conductive organohydrogel as a flexible sensor for synchronous real-time monitoring of traumatic wounds and pro-healing process

Ion-conductive hydrogels (ICHs) offer promising applications in the realm of flexible bioelectronics due to their attributes, such as transparency, flexibility, tissue adhesion, and self-healing. However, it remains a challenge to integrate excellent material properties and bio-properties into ICHs-based smart wearables for intricate biomedical applications. Herein, a multifunctional conductive C-CST/PMC organohydrogel with stretchability, anti-freezing, self-healing, antibacterial, antioxidant, and biocompatibility was synthesized by catechol-conjugated chitosan (C-CS), silk nanofibrils (SNFs), tannic acid (TA), MgCl2/CaCl2, and polyvinyl alcohol (PVA), with a binary solvent system composed of ethylene glycol (EG) and H2O. The C-CST/PMC exhibited excellent mechanical properties (175 kPa stress and 330 % strain), anti-freezing capacity, moisture retention, self-healing performance, and high conductivity (1.76 mS/cm at 25 °C and 1.43 mS/cm at –18 °C). Moreover, we have employed this organohydrogel as a flexible strain sensor for monitoring human movements, achieving a high sensitivity (gauge factor (GF) = 1.20 at 100 % strain) and glorious fatigue resistance (>1000 cycles). Furthermore, the C-CST/PMC displayed good antibacterial, antioxidant, hemo-, and cytocompatibility. In vivo tests on diabetic rats have demonstrated that the C-CST/PMC organohydrogel effectively reduces inflammatory responses and promotes angiogenesis, consequently expediting wound healing. Notably, trials involving the use of this flexible sensor in a medical silicone bionic shoulder have indicated its potential as a wearable electronic device for real-time monitoring of human wound healing progress. Overall, this research contributes novel insights to the design and fabrication of multifunctional flexible sensors that synchronous pro-healing and real-time monitoring of traumatic skin.

Role of the mitochondrial protein cyclophilin D in skin wound healing and collagen secretion.

Central for wound healing is the formation of granulation tissue, which largely consists of collagen and whose importance stretches past wound healing, including being implicated in both fibrosis and skin aging. Cyclophilin D (CyD) is a mitochondrial protein that regulates the permeability transition pore, known for its role in apoptosis and ischemia-reperfusion. To date, the role of CyD in human wound healing and collagen generation has been largely unexplored. Here, we show that CyD was upregulated in normal wounds and venous ulcers, likely adaptive as CyD inhibition impaired reepithelialization, granulation tissue formation, and wound closure in both human and pig models. Overexpression of CyD increased keratinocyte migration and fibroblast proliferation, while its inhibition reduced migration. Independent of wound healing, CyD inhibition in fibroblasts reduced collagen secretion and caused endoplasmic reticulum collagen accumulation, while its overexpression increased collagen secretion. This was confirmed in a Ppif-KO mouse model, which showed a reduction in skin collagen. Overall, this study revealed previously unreported roles of CyD in skin, with implications for wound healing and beyond.

MoS2-poly(sodium4-styrenesulfonate) nanocomposite-based humidity sensor for monitoring wound healing

In this paper, a humidity sensor with high response, high stability and fast response recovery based on MoS2-PSS hybridized sensitive materials was designed, and preliminarily explored for application in noninvasive monitoring of human wound healing. The modification of PSS promoted the increase of S vacancy defects in the MoS2-PSS hybrid materials, which facilitated the rapid adsorption of water molecules and charge transfer. The edge dangling bonds and PSS in MoS2-PSS hybrid materials jointly enhanced the water molecule adsorption capacity and promoted the rapid formation of chemisorbed water layer on materials surface. The formation of chemical bond between MoS2 and PSS makes the hybrid material more stable in structure. The prevents the loss of hydrophilic material caused by the sensor working in high humidity environment for a long time and improves the stability of the sensor. MoS2-PSS humidity sensor exhibites high response (11097), short response/recovery time (5/6 s), low humidity hysteresis (1.6%), and high stability in the 11%-95% RH range. This study not only promotes the development of high-performance sensors, but may also provide a viable option for noninvasive monitoring of wound healing.

Assessing Animal Models to Study Impaired and Chronic Wounds.

Impaired healing wounds do not proceed through the normal healing processes in a timely and orderly manner, and while they do eventually heal, their healing is not optimal. Chronic wounds, on the other hand, remain unhealed for weeks or months. In the US alone, chronic wounds impact ~8.5 million people and cost ~USD 28-90 billion per year, not accounting for the psychological and physical pain and emotional suffering that patients endure. These numbers are only expected to rise in the future as the elderly populations and the incidence of comorbidities such as diabetes, hypertension, and obesity increase. Over the last few decades, scientists have used a variety of approaches to treat chronic wounds, but unfortunately, to date, there is no effective treatment. Indeed, while there are thousands of drugs to combat cancer, there is only one single drug approved for the treatment of chronic wounds. This is in part because wound healing is a very complex process involving many phases that must occur sequentially and in a timely manner. Furthermore, models that fully mimic human chronic wounds have not been developed. In this review, we assess various models currently being used to study the biology of impaired healing and chronic non-healing wounds. Among them, this paper also highlights one model which shows significant promise; this model uses aged and obese db/db-/- mice and the chronic wounds that develop show characteristics of human chronic wounds that include increased oxidative stress, chronic inflammation, damaged microvasculature, abnormal collagen matrix deposition, a lack of re-epithelialization, and the spontaneous development of multi-bacterial biofilm. We also discuss how important it is that we continue to develop chronic wound models that more closely mimic those of humans and that can be used to test potential treatments to heal chronic wounds.

Immunohistochemical analysis of PDGFR-α for wound age determination.

Immunohistochemical analysis of platelet-derived growth factor receptor-α (PDGFR-α) was performed on human skin wounds obtained from forensic autopsy cases. Thirty human skin wounds were collected at different post-infliction intervals as follows: Group I, 4h to 3 days (n = 16); Group II, 4 to 7 days (n = 7); Group III, 9 to 10 days (n = 3); and Group IV, 14 to 20 days (n = 4). Immunopositive reactions for PDGFR-α were not observed in the uninjured human skin specimens. In a semi-quantitative morphometrical analysis, the number of PDGFR-α-positive cells was observed increased in Group II, with the average number of PDGFR-α-positive cells being the highest in Group II. Additionally, in Group II, all specimens showed PDGFR-α-positive cells, with an average number of > 200 cells in five fields of view, suggesting a wound age of 4 to 7 days. Taken together, the immunohistochemical detection of PDGFR-α in human skin wounds can be a useful tool for wound age determination.

Retracted: Identification of the Potential Biomarkers Involved in the Human Oral Mucosal Wound Healing: A Bioinformatic Study.

[This retracts the article DOI: 10.1155/2021/6695245.].

Proteoglycan 4 (PRG4) treatment improves skin wound healing in a porcine model.

Proteoglycan 4 (PRG4) is a boundary lubricant originally identified in articular cartilage and has been since shown to have immunomodulation and antifibrotic properties. Previously, we have demonstrated that recombinant human (rh)PRG4 treatment accelerates auricular cartilage injury closure through an inhibition of the fibrotic response, and promotion of tissue regeneration in mice. The purpose of the current study was to examine the effects of rhPRG4 treatment (vs. a DMSO carried control) on full-thickness skin wound healing in a preclinical porcine model. Our findings suggest that while rhPRG4 did not significantly accelerate nor impede full-thickness skin wound closure, it did improve repair quality by decreasing molecular markers of fibrosis and increasing re-vascularization. We also demonstrated that rhPRG4 treatment increased dermal adipose tissue during the healing process specifically by retaining adipocytes in the wound area but did not inhibit lipolysis. Overall, the results of the current study have demonstrated that rhPRG4 acts as antifibrotic agent and regulates dermal adipose tissue during the healing processes resulting in a tissue with a trajectory that more resembles the native skin vs. a fibrotic patch. This study provides strong rationale to examine if rhPRG4 can improve regeneration in human wounds.

Cigarette smoke and nicotine effect on human mesenchymal stromal cell wound healing and osteogenic differentiation capacity.

Mesenchymal stromal cells (MSCs) play a crucial role in promoting tissue regeneration and healing, particularly in bone tissue. Both smoking and nicotine use are known to delay and inhibit the healing process in patients. This study aims at delineating these cellular effects by comparing the impact of nicotine alone to cigarette smoke with equivalent nicotine content, and shedding light on potential differences in the healing process. We examined how cigarette smoke and nicotine affect the migration, proliferation, and osteogenic differentiation of human patient-derived MSCs in vitro, as well as the secretion of cytokines IL-6 and IL-8. We measured nicotine concentration of the cigarette smoke extract (CSE) to clarify the role of the nicotine in the effect of the cigarette smoke. MSCs exposed to nicotine-concentration-standardized CSE exhibited impaired wound healing capability, and at high concentrations, increased cell death. At lower concentrations, CSE dose-dependently impaired migration, proliferation, and osteogenic differentiation, and increased IL-8 secretion. Nicotine impaired proliferation and decreased PINP secretion. While there was a trend for elevated IL-6 levels by nicotine in undifferentiated MSCs, these changes were not statistically significant. Exposure of MSCs to equivalent concentrations of nicotine consistently elicited stronger responses by CSE and had a more pronounced effect on all studied parameters. Our results suggest that the direct effect of cigarette smoke on MSCs contributes to impaired MSC function, that adds to the nicotine effects. Cigarette smoke extract reduced the migration, proliferation, and osteogenic differentiation in MSCs in vitro, while nicotine alone reduced proliferation. Cigarette smoke impairs the osteogenic and regenerative ability of MSCs in a direct cytotoxic manner. Cytotoxic effect of nicotine alone impairs regenerative ability of MSCs, but it only partly explains cytotoxic effects of cigarette smoke. Direct effect of cigarette smoke, and partly nicotine, on MSCs could contribute to the smoking-related negative impact on long-term bone health, especially in bone healing.

Optical Manipulation of Fibroblasts with Femtosecond Pulse and CW Laser

Using tight focusing light, optical tweezers (OT) are tools that can manipulate and capture microscopic particles and biological cells as well as characterize a wide range of micro and nanomaterials. In this paper, we focused on fibroblasts, which are widely used in the biomedical area for a variety of purposes, including promoting human wound healing and preventing the early proliferation of tumor cells. We first built an optical tweezer experimental platform, using an 808 nm continuous-wave laser as the capture light source, to confirm that the device can precisely control the movement of single or multiple particles as well as fibroblasts. Then, a 1030 nm femtosecond laser was employed as the capture light source to study the manipulation of microparticles and fibroblasts at different powers. Lastly, a protracted manipulation protocol was used to prevent the fibroblasts from adhering to the wall. This method can be used to isolate and precisely block adherent growth of fibroblasts in cell populations. This experimental result can be further extended to other biological cells.

Successful topical treatment of human biofilms using multiple antibiotic elution from a collagen-rich hydrogel

Chronic non-healing wounds significantly strain modern healthcare systems, affecting 1–2% of the population in developed countries with costs ranging between $28.1 and $96.8 billion annually. Additionally, it has been established that chronic wounds resulting from comorbidities, such as peripheral vascular disease and diabetes mellitus, tend to be polymicrobial in nature. Treatment of polymicrobial chronic wounds with oral and IV antibiotics can result in antimicrobial resistance, leading to more difficult-to-treat wounds. Ideally, chronic ulcers would be topically treated with antibiotic combinations tailored to the microbiome of a patient’s wound. We have previously shown that a topical collagen-rich hydrogel (cHG) can elute single antibiotics to inhibit bacterial growth in a manner that is nontoxic to mammalian cells. Here, we analyzed the microbiology of cultures taken from human patients diagnosed with diabetes mellitus suffering from chronic wounds present for more than 6 weeks. Additionally, we examined the safety of the elution of multiple antibiotics from collagen-rich hydrogel in mammalian cells in vivo. Finally, we aimed to create tailored combinations of antibiotics impregnated into cHG to successfully target and treat infections and eradicate biofilms cultured from human chronic diabetic wound tissue. We found that the majority of human chronic wounds in our study were polymicrobial in nature. The elution of multiple antibiotics from cHG was well-tolerated in mammalian cells, making it a potential topical treatment of the polymicrobial chronic wound. Finally, combinations of antibiotics tailored to each patient’s microbiome eluted from a collagen-rich hydrogel successfully treated bacterial cultures isolated from patient samples via an in vitro assay.