Silicon-Carbon Dots-Loaded Mesoporous Silica Nanocomposites (mSiO2@SiCDs): An Efficient Dual Inhibitor of Cu2+-Mediated Oxidative Stress and Aß Aggregation for Alzheimer's Disease.

The redox-active metal ions, especially Cu2+, are highly correlated to Alzheimer's disease (AD) by causing metal ion-mediated oxidative stress and toxic metal-bound ß-amyloid (Aß) aggregates. Numerous pieces of evidence have revealed that the regulation of metal homeostasis could be an effective therapeutic strategy for AD. Herein, in virtue of the interaction of both amino-containing silane and ethylenediaminetetraacetic acid disodium salt for Cu2+, the silicon-carbon dots (SiCDs) are deliberately prepared using these two raw materials as the cocarbon source; meanwhile, to realize the local enrichment of SiCDs and further maximize the chelating ability to Cu2+, the SiCDs are feasibly loaded to the biocompatible mesoporous silica nanoparticles (mSiO2) with the interaction between residual silane groups on SiCDs and silanol groups of mSiO2. Thus-obtained nanocomposites (i.e., mSiO2@SiCDs) could serve as an efficient Cu2+ chelator with satisfactory metal selectivity and further modulate the enzymic activity of free Cu2+ and the Aß42-Cu2+ complex to alleviate the pathological oxidative stress with an anti-inflammatory effect. Besides, mSiO2@SiCDs show an inspiring inhibitory effect on Cu2+-mediated Aß aggregation and further protect the neural cells against the toxic Aß42-Cu2+ complex. Moreover, the transgenic Caenorhabditis elegans CL2120 assay demonstrates the protective efficacy of mSiO2@SiCDs on Cu2+-mediated Aß toxicity in vivo, indicating its potential for AD treatment.

Observation and assessment of the immediate use of a silicon hydrogel contact lens after transepithelial corneal cross linking: a prospective study.

BACKGROUND: Transepithelial corneal crosslinking (CXL) is a novel surgical approach for the treatment of keratoconus, which is a bilateral asymmetrical ophthalmological disease accompanied by progressive corneal ectasia. Silicon hydrogel (SiH) contact lenses have been extensively used in clinical ophthalmologic medicine, as a postoperative ophthalmological intervention. However, the ideal lens application duration after transepithelial CXL remains uncertain. Here, we aimed to investigate the effects and comfort of immediate corneal contact lens use after transepithelial CXL for keratoconus. METHODS: In this prospective study, 60 patients with keratoconus who underwent transepithelial CXL treatment were enrolled from September 2021 to January 2023 with a male:female ratio of 39:21, and an average age of 25.42 ± 5.47 years. The patients were divided randomly into two groups: group A contained 30 patients wearing silicone hydrogel contact lenses for 7 days postoperatively, and group B contained 30 patients wearing the same contact lenses for 3 days. Ten subjective ophthalmologic symptoms were surveyed by the patients, including pain, photophobia, foreign body sensation, tearing, burning, blurred vision, dry eyes, difficulty opening the eyes, astringency, and stinging. Ophthalmologic signs, including corneal edema and conjunctival congestion, were recorded by a single clinician on postoperative days 1, 3, and 7. RESULTS: Each surgical procedure was readily performed without complications, and both groups postoperative day 7 (P = 0.04), where group B scored (0.01 ± 0.41) lesser than group A (0.12 ± 0.29), whilst corneal edema in both groups recorded significantly different on postoperative days 5 and 7 (group A demonstrated the result of 0.17 ± 0.14 and 0.08 ± 0.11 for the respective days, whereas group B indicated 0.10 ± 0.13 and 0.03 ± 0.07 at the corresponding times). CONCLUSIONS: Immediate use of silicone hydrogel corneal lenses after transepithelial CXL effectively alleviates postoperative ocular distress, particularly with a three-day use period as the ideal duration.

Orally Administered Silicon Hydrogen Nanomaterials as Target Therapy to Treat Intestinal Diseases.

The occurrence and development of inflammatory bowel diseases (IBDs) are inextricably linked to the excessive production of reactive oxygen species (ROS). Thus, there is an urgent need to develop innovative tactics to combat IBDs and scavenge excess ROS from affected areas. Herein, silicon hydrogen nanoparticles (SiH NPs) with ROS-scavenging ability were prepared by etching Si nanowires (NWs) with hydrogen fluoride (HF) to alleviate the symptoms associated with IBD by orally targeting the inflamed colonic sites. The strong reductive Si-H bonds showed excellent stability in the gastric and intestinal fluids, which exhibited efficient ROS-scavenging effects to protect cells from high oxidative stress-induced death. After oral delivery, the negatively charged SiH NPs were specifically adsorbed to the positively charged inflammatory epithelial tissues of the colon for an extended period via electrostatic interactions to prolong the colonic residence time. SiH NPs exhibited significant preventive and therapeutic effects in dextran sodium sulfate-induced prophylactic and therapeutic mouse models by inhibiting colonic shortening, reducing the secretion of pro-inflammatory cytokines, regulating macrophage polarization, and protecting the colonic barrier. As determined using 16S rDNA high-throughput sequencing, the oral administration of SiH NPs treatment led to changes in the abundance of the intestinal microbiome, which improved the bacterial diversity and restored the relative abundance of beneficial bacteria after the inflamed colon. Overall, our findings highlight the broad application of SiH-based anti-inflammatory drugs in the treatment of IBD and other inflammatory diseases.

Effect of the new silicon-based agent on the symptoms of interstitial pneumonitis.

Interstitial pneumonia (IP) is a collective term for diseases whose main lesion is fibrosis of the pulmonary interstitium, and the prognosis associated with acute exacerbation of these conditions is often poor. Therapeutic agents are limited to steroids, immunosuppressants, and antifibrotic drugs, which and have many side effects; therefore, the development of new therapeutic agents is required. Because oxidative stress contributes to lung fibrosis in IP, optimal antioxidants may be effective for the treatment of IP. Silicon (Si)-based agents, when administered orally, can continuously generate a large amount of antioxidant hydrogen in the intestinal tract. In this study, we investigated the effect of our Si-based agent on methotrexate-induced IP, using the IP mouse models. Pathological analysis revealed that interstitial hypertrophy was more significantly alleviated in the Si-based agent-treated group than in the untreated group (decreased by about 22%; P < 0.01). Moreover, additional morphological analysis demonstrated that infiltration of immune cells and fibrosis in the lungs were significantly inhibited by treatment with the Si-based agent. Furthermore, Si-based agent reduced oxidative stress associated with IP by increasing blood antioxidant activity. (increased by about 43%; P < 0.001). Taken together, these results suggest that Si-based agents can be effective therapeutic agents for IP.

Chemo-photodynamic Activity of Silicon Phthalocyanines Bearing Cyclooxygenase Inhibitors on Colorectal Cancer Cell Lines.

Colorectal cancer ranks as the third most lethal cancer worldwide, resulting in over 1 million cases and 900 000 deaths per year. According to population-based studies, administration of long-term non-steroidal anti-inflammatory drugs (NSAIDs) was proven to reduce the risk of a subject developing colorectal cancer. In the present study, the anti-cancer activity of two different NSAIDs, sulindac- (Pc-1) or diclofenac-substituted (Pc-2) asymmetric silicon phthalocyanine derivatives, was evaluated in four different colorectal cancer cell lines bearing various carcinogenic mutations. In this context, the IC50 values of each compound after 24 and 48 h were determined on HCT116, SW480, LoVo, and HT29 cell lines, and the effects of the compounds on programmed cell death pathways apoptosis and autophagy, their impact on cell cycle progression, and the effect of NSAID moieties they bear on COX-1 and COX-2 proteins were analyzed. In addition, the photophysical and photochemical properties of a synthesized Pc derivative bearing axial diclofenac and triethylene glycol groups (Pc-2) have been investigated, and the compound has been characterized by using different analytical techniques. Our results indicated that both compounds inhibit COX protein expression levels, activate apoptosis in all cell lines, and lead to cell cycle arrest in the G2/M phase, depending on the COX expression profiles of the cell lines, indicating that NSAIDs can be coupled with Pc's to achieve increased anti-cancer activity, especially on cancer cells known to have high COX activity.

Efficient dose-rate correction of silicon diode relative dose measurements.

PURPOSE: Silicon diodes are often the detector of choice for relative dose measurements, particularly in the context of radiotherapy involving small photon beams. However, a major drawback lies in their dose-rate dependency. Although ionization chambers are often too large for small field output factor (OF) measurements, they are valuable instruments to provide reliable percent-depth dose (PDD) curves in reference beams. The aim of this work is to propose a practical and accurate method for the characterization of silicon diode dose-rate dependence correction factors using ionization chamber measurements as a reference. METHODS: The robustness of ionization chambers for PDD measurements is used to quantify the dose-rate dependency of a diode detector. A mathematical formalism, which exploits the error induced in percent-depth ionization (PDI) curves for diodes by their dose-rate dependency, is developed to derive a dose-rate correction factor applicable to diode relative measurements. The method is based on the definition of the recombination correction factor given in the addendum to TG 51 and is applied to experimental measurements performed on a CyberKnife M6 radiotherapy unit using a PTW 60012 diode detector. A measurement-based validation is provided by comparing corrected PDI curves to measurements performed with a PTW 60019 diamond detector, which does not exhibit dose-rate dependence. RESULTS: Results of dose-rate correction factors for PDI curves, off-axis ratios (OARs), tissue-phantom ratios, and small field OFs are coherent with the expected behavior of silicon diode detectors. For all considered setups and field sizes, the maximum correction and the maximum impact of the uncertainties induced by the correction are obtained for OARs for the 60 mm collimator, with a correction of 2.5% and an uncertainty of 0.34%. For OFs, corrections range from 0.33% to 0.82% for all field sizes considered, and increase with the reduction of the field size. Comparison of PDI curves corrected for dose-rate and for in-depth beam quality variations illustrates excellent agreement with measurements performed using the diamond detector. CONCLUSION: The proposed method allows the efficient and precise correction of the dose-rate dependence of silicon diode detectors in the context of clinical relative dosimetry.

A Deep Dive: SIWV Tetra-Peptide Enhancing the Penetration of Nanotherapeutics into the Glioblastoma.

Glioblastoma multiforme (GBM) is the most aggressive malignant tumor. It is difficult to regulate GBM using conventional chemotherapy-based methods due to its anatomical structure specificity, low drug targeting ability, and limited penetration depth capability to reach the tumor interior. Numerous approaches have been proposed to overcome such issues, including nanoparticle-based drug delivery system (DDS) with the development of GBM site targeting and penetration depth enhancing moieties (e.g., peptides, sugars, proteins, etc.). In this study, we prepared four different types of nanoparticles, which are based on porous silicon nanoparticles (pSiNPs) incorporating polyethylene glycol (PEG), iRGD peptide (well-known cancer targeting peptide), and SIWV tetra-peptide (a recently disclosed GBM-targeting peptide), and analyzed their deep-tumor penetration abilities in cell spheroids, in GBM patient-derived tumoroids, and in GBM xenograft mice. We found that SIWV tetra-peptide significantly enhanced the penetration depth of pSiNPs, and its therapeutic formulation (temozolomide-loaded/SIWV-functionalized pSiNPs) showed a higher anticancer efficacy compared with other formulations. These findings hold great promise for the development of nanotherapeutics and peptide-conjugated drugs for GBM.

Evaluation of the Effect of Inactivated Transmissible Gastroenteritis Virus Vaccine with Nano Silicon on the Phenotype and Function of Porcine Dendritic Cells.

A transmissible gastroenteritis virus (TGEV) is a porcine enteropathogenic coronavirus, causing acute swine enteric disease especially in suckling piglets. Mesoporous silica nanoparticles (MSNs) are safe vaccine adjuvant, which could enhance immune responses. Our previous research confirmed that nano silicon had immune-enhancing effects with inactivated TGEV vaccine. In this study, we further clarified the immune-enhancing mechanism of the inactivated TGEV vaccine with MSNs on porcine dendritic cells (DCs). Our results indicated that the inactivated TGEV vaccine with MSNs strongly enhanced the activation of the DCs. Expressions of TLR3, TLR5, TLR7, TLR9, and TLR10, cytokines IFN-α, IL-1ß, IL-6, IL-12, and TNF-α, cytokine receptor CCR-7 of immature DCs were characterized and showed themselves to be significantly higher in the inactivated TGEV vaccine with the MSN group. In summary, the inactivated TGEV vaccine with MSNs has effects on the phenotype and function of porcine DCs, which helps to better understand the immune-enhancing mechanism.

Intravital Whole-Process Monitoring Thermo-Chemotherapy Via 2D Silicon Nanoplatform: A Macro Guidance and Long-Term Microscopic Precise Imaging Strategy.

Tumor angiogenesis is a complex process that is unamenable to intravital whole-process monitoring, especially on microscopic assessment of tumor microvessel and quantifying microvascular hemodynamics before and after the nanotherapeutics, which hinder the understanding of nanotheranostics outcomes in tumor treatment. Herein, a new photoacoustic (PA) imaging-optical coherence tomography angiography (OCTA)-laser speckle (LS) multimodal imaging strategy is first proposed, which is not only able to precisely macro guide the thermo-chemotherapy of tumor by monitoring blood oxygen saturation (SaO2 ) and hemoglobin content (HbT), but also capable of long-term microscopic investigating the microvessel morphology (microvascular density) and hemodynamics changes (relative blood flow) before and after the nanotherapeutics in vivo. Moreover, to realize the tumor thermo-chemotherapy treatment based on this novel multimodal imaging strategy, a 2D 5-fluorouracil silicon nanosheets (5-Fu-Si NSs) therapeutic agent is designed. Furthermore, 2D high-resolution tumor microvascular images in different stage display that tendency of the thermo-chemotherapy effect is closely associated with tumor angiogenesis. Taken together, the investigations establish the fundamental base in theory and technology for further tailoring the novel specific diagnosis and treatment strategy in tumor. More importantly, this technique will be beneficial to evaluate the tumor microvascular response to nanotherapeutics at microscale.

Novel hydrogen-producing Si-based agent reduces oxidative stress, and improves sperm motility and in vitro fertilization rate in varicocoele.

BACKGROUND: Varicocoele-induced male infertility potentially involves oxidative stress. Although varicocoelectomy is recommended for varicocoele patients presenting abnormal semen findings, no pharmacotherapeutic methods currently exist. We have recently developed a silicon-based agent that produces hydrogen by the reaction with water. OBJECTIVES: This study aimed to investigate the therapeutic effects of oral administration of a Si-based agent on varicocoele rat. MATERIALS AND METHODS: Twenty-one rats were divided into four groups: varicocoele + normal diet (n = 5), varicocoele + Si-based agent-supplemented diet (n = 6), sham + normal diet (n = 5), and sham + Si-based agent-supplemented diet (n = 5). All rats were euthanized four weeks after surgery. RESULTS: The mean left epididymal sperm motility was 74.4% in the sham group, 72.3% in the sham + Si group, 57.6% in the varicocoele group, and 66.9% in the varicocoele + Si group. Epididymal sperm motility was significantly lower in the varicocoele group, but was significantly higher upon Si-based agent ingestion (P < .01). The mean left testicular weight, Johnsen's score, and left epididymal sperm concentration did not differ significantly between groups. The 8-OHdG concentration and DNA fragmentation rate were significantly increased in the varicocoele group, but were significantly decreased in the Si-based agent intake group (P < .01). Additionally, the IVF rate was significantly lower in the varicocoele group (26.3%) compared with the sham group (73.4%; P < .01), and was significantly higher in the varicocoele + Si group (51.8%) compared with the varicocoele group (P < .05), indicating that the Si-based agent improves IVF rates. DISCUSSION AND CONCLUSION: Oral intake of the silicon-based agent improves epididymal sperm motility and in vitro fertilization rates through hydrogen production and subsequent reduction of oxidative stress. Considering the lack of effective noninvasive methods, this Si-based agent is potentially applicable for treating varicocoele-induced abnormal semen parameters.

Adoption of a Newly Introduced Dermal Matrix: Preliminary Experience and Future Directions.

INTRODUCTION: Acellular dermal matrix (ADM) products are adopted in the management of injuries to soft tissues. ADMs have been increasingly employed for their clinical advantages, and they are acquiring relevance in the future of plastic surgery. The aim of our study is to evaluate the application of ADMs in our patients who could not undergo fast reconstruction. MATERIALS AND METHODS: We performed a retrospective study on 12 patients who underwent ADM placement for scalp and limb surgical reconstructions at the Humanitas Research Hospital, Rozzano (Milano), Italy. Wounds resulted from 9 tumor resections and 3 chronic ulcers. The ADM substrate used to treat these lesions was PELNAC™ (Gunze, Japan), a double-layered matrix composed of atelocollagen porcine tendon and silicon reinforcement. All patients underwent a second surgical operation to complete the treatment with a full-thickness skin graft to cover the lesion. RESULTS: In this study, 12 patients were treated with PELNAC™: 11 out of 12 patients showed a good attachment over a median time of 21.3 days (range 14-27). After almost 23 days, all patients were ready to undergo a full-thickness skin grafting. CONCLUSION: This study assesses the benefits of PELNAC™ and proposes this method as an alternative to traditional approaches, especially in situations where the latter techniques cannot be applied.

Efficacy of a Si-based agent against developing renal failure in a rat remnant kidney model.

Chronic renal failure is exacerbated by oxidative stress, and this condition is difficult to treat in advanced stages. Because of the lack of effective treatments, the disease is a global public health concern. We developed a Si-based agent that continuously generates hydrogen for more than 24 h by reacting with water under conditions similar to those in the gastrointestinal tract. Given the efficacy of hydrogen in the treatment of conditions associated with oxidative stress, we examined whether the Si-based agent had beneficial effects on the development of renal failure. The Si-based agent was orally administered to rats that were developing renal failure. Rats underwent 5/6 nephrectomy to establish a remnant kidney model. Specifically, on day -7, rats underwent right 2/3 nephrectomy, followed by light nephrectomy on day 0. Starting on day -3, the rats were administered a control or Si-based agent-containing diet for 8 weeks. Compared with the findings in control rats, the Si-based agent greatly suppressed the increases of both serum creatinine and urinary protein levels. All analyzed parameters of oxidative stress were significantly suppressed in the Si-based agent groups. Histopathological examination illustrated that glomerular hypertrophy was suppressed by the treatment. Quantitative real-time reverse transcription-polymerase chain reaction revealed that sirtuin 1 and heme oxygenase-1 expression was increased in the Si-based agent groups, suggesting improved antioxidant activity and reduced hypoxia. In addition, caspase-3 and interleukin-6 expression was suppressed in the Si-based agent groups, indicating the alleviation of apoptosis and inflammation. In conclusion, oral administration of a Si-based agent resulted in renoprotective effects, presumably by suppressing oxidative stress via hydrogen generation.

Group IV nanodots: synthesis, surface engineering and application in bioimaging and biotherapy.

Group IV nanodots (NDs) mainly including carbon (C), silicon (Si), germanium (Ge) have aroused much attention as one type of important nanomaterials that are widely studied in optoelectronics, semiconductors, sensors and biomedicine-related fields owing to the low cost of synthesis, good stability, excellent biocompatibility, and some attractive newly emerged properties. In this review, the synthesis, surface engineering and application in bioimaging and biotherapy of group IV NDs are summarized and discussed. The recent progress in the rational synthesis and functionalization, specific therapy-related properties, together with in vivo and in vitro bioimaging are highlighted. Their new applications in biotherapy such as photothermal therapy (PTT) and photodynamic therapy (PDT) are illustrated with respect to C, Si and Ge NDs. The current challenges and future applications of these emerging materials in bioimaging and biotherapy are presented. This review provides readers with a distinct perspective of the group IV NDs nanomaterials for synthesis and surface engineering, and newly emerging properties related to applications in biomedicine.

Renoprotective and neuroprotective effects of enteric hydrogen generation from Si-based agent.

We have developed Si-based agent which can generate a large amount of hydrogen. Si-based agent continues generating hydrogen for more than 24 h by the reaction with water under conditions similar to those in bowels, i.e., pH8.3 and 36 °C, and generates ~400 mL hydrogen. To investigate beneficial effects for diseases associated with oxidative stress, Si-based agent is administered to remnant kidney rats and Parkinson's disease mice. Rats are fed with control or Si-based agent-containing diet for 8 weeks. Si-based agent is found to greatly suppress the development of renal failure and the parameters of oxidative stress. Treatment with Si-based agent in a mouse model of hemi-Parkinson's disease induced by 6-hydroxydopamine attenuated degeneration of dopaminergic neurons and prevented impairment of motor balance and coordination. These findings indicate that the Si-based agent shows renoprotective and neuroprotective effects presumably via suppression of oxidative stress by generation of hydrogen.

Silicon restrains drought-induced ROS accumulation by promoting energy dissipation in leaves of tomato.

Energy dissipation plays a crucial role in mediating responses to oxidative stress in plants. Although the beneficial effects of silicon on plant resistance to drought stress have been well documented, the potential interactions between energy dissipation and Si in response to drought stress have not been examined. Here, a project was initiated that focused on the relationship between energy dissipation and the functions of Si. In this study, silicon-mediated proteins promoted the consumption of light energy capture and NPQ in chloroplasts. Additionally, we confirmed that the role of silicon-mediated energy dissipation in mitochondria was important for photosynthetic optimization. The energy dissipation in mitochondria was improved, which further optimized the energy dissipation in chloroplasts via Si-mediated alternative oxidase and the malate/oxaloacetate shuttle. ROS accumulation decreased because of the silicon-mediated energy dissipation.

Biocompatibility between Silicon or Silicon Carbide surface and Neural Stem Cells.

Silicon has been widely used as a material for microelectronic for more than 60 years, attracting considerable scientific interest as a promising tool for the manufacture of implantable medical devices in the context of neurodegenerative diseases. However, the use of such material involves responsibilities due to its toxicity, and researchers are pushing towards the generation of new classes of composite semiconductors, including the Silicon Carbide (3C-SiC). In the present work, we tested the biocompatibility of Silicon and 3C-SiC using an in vitro model of human neuronal stem cells derived from dental pulp (DP-NSCs) and mouse Olfactory Ensheathing Cells (OECs), a particular glial cell type showing stem cell characteristics. Specifically, we investigated the effects of 3C-SiC on neural cell morphology, viability and mitochondrial membrane potential. Data showed that both DP-NSCs and OECs, cultured on 3C-SiC, did not undergo consistent oxidative stress events and did not exhibit morphological modifications or adverse reactions in mitochondrial membrane potential. Our findings highlight the possibility to use Neural Stem Cells plated on 3C-SiC substrate as clinical tool for lesioned neural areas, paving the way for future perspectives in novel cell therapies for neuro-degenerated patients.

Silicene: Wet-Chemical Exfoliation Synthesis and Biodegradable Tumor Nanomedicine.

Silicon-based biomaterials play an indispensable role in biomedical engineering; however, due to the lack of intrinsic functionalities of silicon, the applications of silicon-based nanomaterials are largely limited to only serving as carriers for drug delivery systems. Meanwhile, the intrinsically poor biodegradation nature for silicon-based biomaterials as typical inorganic materials also impedes their further in vivo biomedical use and clinical translation. Herein, by the rational design and wet chemical exfoliation synthesis of the 2D silicene nanosheets, traditional 0D nanoparticulate nanosystems are transformed into 2D material systems, silicene nanosheets (SNSs), which feature an intriguing physiochemical nature for photo-triggered therapeutics and diagnostic imaging and greatly favorable biological effects of biocompatibility and biodegradation. In combination with DFT-based molecular dynamics (MD) calculations, the underlying mechanism of silicene interactions with bio-milieu and its degradation behavior are probed under specific simulated physiological conditions. This work introduces a new form of silicon-based biomaterials with 2D structure featuring biodegradability, biocompatibility, and multifunctionality for theranostic nanomedicine, which is expected to promise high clinical potentials.

A Novel Silicon Device for the Packing of Cutaneous Abscesses.

BACKGROUND: Superficial skin abscesses are commonly encountered in emergency medicine practice. Standard treatment includes incision, drainage, and often packing with a gauze strip. The packing component of the procedure has several negative potential outcomes, is painful, and necessitates a return visit for removal. DISCUSSION: Here we report the first case in which a novel silicon packing device was utilized. The patient presented with a facial abscess, which was incised and drained. The novel device was inserted, and removed by the patient independently, without complication. Both patient and provider reported satisfaction with the novel procedure, and noted low pain scores. CONCLUSIONS: This device has the potential to replace traditional packing, and will require further study through a controlled trial to assess for safety and efficacy.

Putty Index for Tripoding.

Precise orientation and transfer of the selected path of insertion and removal is a critical step in cast removable partial denture prosthesis design. An easy technique for registering the same is described using addition silicon putty and a used diamond disk.

Silicon foil patching for blast tympanic membrane perforation: a retrospective study.

AIM: To establish whether covering the tympanic membrane perforation after war blast injury with silicon foil can enhance the ear drum healing rate and to determine the appropriate timing of silicon patching. METHODS: We retrospectively analyzed the charts of 210 patients wounded during the Homeland War in Croatia 1991-1995, with 315 blast tympanic membrane perforations. In 44 patients (61 perforations), the eardrum perforation was covered by silicon foil, whereas in 166 patients (254 perforations) it was left to heal spontaneously. The patients who underwent the patching procedure were divided in two groups according to the time period between the blast injury and the procedure: 38 perforations were treated within 3 days and 23 perforations were treated 4 to 6 days after the blast injury. RESULTS: The rate of tympanic membrane healing in the silicon foil patching group was significantly higher (91.8%) than that in the group of perforations left to heal spontaneously (79.9%, P=0.029). The healing rate was significantly higher in the group treated within 3 days after the blast injury (97.4%) than in the group treated 4 to 6 days after the injury (82.6%, P=0.042). CONCLUSION: Covering the perforation after the war blast injury with silicon foil significantly improves the rate of tympanic membrane healing. To obtain the best healing outcome, the procedure should be performed within the first 72 hours after the trauma.