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1.
Pediatr Surg Int ; 40(1): 182, 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-38980431

ABSTRACT

PURPOSE: Previous studies have shown a higher recurrence rate and longer operative times for thoracoscopic repair (TR) of congenital diaphragmatic hernia (CDH) compared to open repair (OR). An updated meta-analysis was conducted to re-evaluate the surgical outcomes of TR. METHODS: A comprehensive literature search comparing TR and OR in neonates was performed in accordance with the PRISMA statement (PROSPERO: CRD42020166588). RESULTS: Fourteen studies were selected for quantitative analysis, including a total of 709 patients (TR: 308 cases, OR: 401 cases). The recurrence rate was higher [Odds ratio: 4.03, 95% CI (2.21, 7.36), p < 0.001] and operative times (minutes) were longer [Mean Difference (MD): 43.96, 95% CI (24.70, 63.22), p < 0.001] for TR compared to OR. A significant reduction in the occurrence of postoperative bowel obstruction was observed in TR (5.0%) compared to OR (14.8%) [Odds ratio: 0.42, 95% CI (0.20, 0.89), p = 0.02]. CONCLUSIONS: TR remains associated with higher recurrence rates and longer operative times. However, the reduced risk of postoperative bowel obstruction suggests potential long-term benefits. This study emphasizes the importance of meticulous patient selection for TR to mitigate detrimental effects on patients with severe disease.


Subject(s)
Hernias, Diaphragmatic, Congenital , Herniorrhaphy , Thoracoscopy , Humans , Hernias, Diaphragmatic, Congenital/surgery , Thoracoscopy/methods , Herniorrhaphy/methods , Infant, Newborn , Operative Time , Postoperative Complications/epidemiology , Treatment Outcome , Recurrence
2.
BMJ Open ; 14(6): e081153, 2024 Jun 11.
Article in English | MEDLINE | ID: mdl-38862230

ABSTRACT

INTRODUCTION: Oesophageal discontinuity remains a challenge for thoracic and foregut surgeons globally. Whether arising emergently after catastrophic oesophageal or gastric disruption or arising in the elective setting in the case of staged reconstruction for esophagectomy or long gap atresia in the paediatric population, comprehensive review of this patient population remains unexplored within the surgical literature.The goal of this scoping review is to map the landscape of literature exploring the creation and takedown of cervical oesophagostomy with the intent to answer four questions (1) What are the primary indications for oesophageal discontinuity procedures? (2) What are the disease-specific and healthcare utilisation outcomes for oesophageal discontinuity procedures? (3) What is the primary indication for reversal procedures? (4) What are the disease-specific and healthcare utilisation outcomes for reversal procedures? METHODS: This review will follow the Arksey and O'Malley (2005) framework for scoping reviews. Paediatric (<18 years old) and adult (>18 years old) patients, who have received a cervical oesophagostomy in the context of a gastrointestinal discontinuity procedure or those who have had reversal of a cervical oesophagostomy, will be included for analysis. We will search MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) databases for papers from 1990 until 2023. Interventional trials, prospective and retrospective observational studies, reviews, case series and qualitative study designs will be included. Two authors will independently review all titles, abstracts and full texts to determine which studies meet the inclusion criteria. ETHICS AND DISSEMINATION: No ethics approval is required for this review. Results will be disseminated through scientific presentations and relevant conferences targeted for researchers examining upper gastrointestinal/foregut surgery. REGISTRATION DETAILS: This protocol is registered with Open Science Framework (osf.io/s3b4g).


Subject(s)
Esophagostomy , Humans , Esophagostomy/methods , Esophagectomy/methods , Research Design , Esophageal Atresia/surgery , Esophagus/surgery , Review Literature as Topic
3.
Nucleic Acids Res ; 52(8): 4313-4327, 2024 May 08.
Article in English | MEDLINE | ID: mdl-38407308

ABSTRACT

The complex formed by Ku70/80 and DNA-PKcs (DNA-PK) promotes the synapsis and the joining of double strand breaks (DSBs) during canonical non-homologous end joining (c-NHEJ). In c-NHEJ during V(D)J recombination, DNA-PK promotes the processing of the ends and the opening of the DNA hairpins by recruiting and/or activating the nuclease Artemis/DCLRE1C/SNM1C. Paradoxically, DNA-PK is also required to prevent the fusions of newly replicated leading-end telomeres. Here, we describe the role for DNA-PK in controlling Apollo/DCLRE1B/SNM1B, the nuclease that resects leading-end telomeres. We show that the telomeric function of Apollo requires DNA-PKcs's kinase activity and the binding of Apollo to DNA-PK. Furthermore, AlphaFold-Multimer predicts that Apollo's nuclease domain has extensive additional interactions with DNA-PKcs, and comparison to the cryo-EM structure of Artemis bound to DNA-PK phosphorylated on the ABCDE/Thr2609 cluster suggests that DNA-PK can similarly grant Apollo access to the DNA end. In agreement, the telomeric function of DNA-PK requires the ABCDE/Thr2609 cluster. These data reveal that resection of leading-end telomeres is regulated by DNA-PK through its binding to Apollo and its (auto)phosphorylation-dependent positioning of Apollo at the DNA end, analogous but not identical to DNA-PK dependent regulation of Artemis at hairpins.


Subject(s)
DNA-Activated Protein Kinase , DNA-Binding Proteins , Endonucleases , Telomere , DNA-Activated Protein Kinase/metabolism , DNA-Activated Protein Kinase/genetics , Telomere/metabolism , Telomere/genetics , Humans , DNA-Binding Proteins/metabolism , DNA-Binding Proteins/genetics , Endonucleases/metabolism , Endonucleases/genetics , DNA End-Joining Repair , Nuclear Proteins/metabolism , Nuclear Proteins/genetics , Ku Autoantigen/metabolism , Ku Autoantigen/genetics , Protein Binding , DNA Breaks, Double-Stranded , Phosphorylation , DNA/metabolism , DNA/chemistry , DNA/genetics
4.
Nat Struct Mol Biol ; 30(9): 1346-1356, 2023 09.
Article in English | MEDLINE | ID: mdl-37653239

ABSTRACT

Telomeres replicated by leading-strand synthesis lack the 3' overhang required for telomere protection. Surprisingly, resection of these blunt telomeres is initiated by the telomere-specific 5' exonuclease Apollo rather than the Mre11-Rad50-Nbs1 (MRN) complex, the nuclease that acts at DNA breaks. Without Apollo, leading-end telomeres undergo fusion, which, as demonstrated here, is mediated by alternative end joining. Here, we show that DNA-PK and TRF2 coordinate the repression of MRN at blunt mouse telomeres. DNA-PK represses an MRN-dependent long-range resection, while the endonuclease activity of MRN-CtIP, which could cleave DNA-PK off of blunt telomere ends, is inhibited in vitro and in vivo by the iDDR of TRF2. AlphaFold-Multimer predicts a conserved association of the iDDR with Rad50, potentially interfering with CtIP binding and MRN endonuclease activation. We propose that repression of MRN-mediated resection is a conserved aspect of telomere maintenance and represents an ancient feature of DNA-PK and the iDDR.


Subject(s)
DNA Breaks , DNA-Activated Protein Kinase , Animals , Mice , Endonucleases , Telomere , DNA
5.
Healthcare (Basel) ; 11(4)2023 Feb 16.
Article in English | MEDLINE | ID: mdl-36833125

ABSTRACT

Health-related quality is of life of great importance in cancer care. This prospective study aimed to evaluate the impact of chemotherapy and bevacizumab on the activities of daily living, cancer symptoms, and general well-being in 59 metastatic colorectal cancer patients. We gathered information using the EORTC QLQ-C30 and QLQ-CR29 questionnaires. The paired sample t-test, MANOVA test, and Pearson's correlation test were used to analyze the presence of significant differences in mean scores before and after 6 months of treatment. The results revealed significant differences in the functioning and symptoms that influence patients' quality of life after 6 months of treatment: increased pain (p = 0.003), nausea and vomiting (p = 0.003), diarrhea (p = 0.021) and decreased appetite (p = 0.003). At the same time, there were several aspects that improved the quality of life. Increases in emotional function (p = 0.009), cognitive function (p = 0.033), and perception of body image (p = 0.026) were observed after 6 months of treatment. Elderly patients reported a higher frequency of stools (p = 0.028), and young patients had increased concerns about body perception (p = 0.047). Assessing the quality of life of metastatic colorectal cancer patients is an important way to identify and treat symptoms related to both cancer and therapy by establishing a holistic care plan and implementing measures to increase the quality of life.

6.
Nanomaterials (Basel) ; 12(3)2022 Feb 05.
Article in English | MEDLINE | ID: mdl-35159894

ABSTRACT

In this work, thin films of lamellar clays were deposited by laser techniques (matrix assisted pulsed laser evaporation (MAPLE) and pulsed laser deposition (PLD)). The focus of this paper is the optimization of deposition parameters for the production of highly oriented crystalline films. The films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Contact angle measurements were employed to identify the wetting properties of the deposited thin films. Hydrophobic to superhydrophilic films can be prepared by using different deposition techniques and deposition parameters. MAPLE led to superhydrophilic films with contact angles in the range 4°-8°, depending on the microstructure and surface roughness at micro and nano scale. The 1064 nm PLD had a high deposition rate and produced a textured film while at λ = 193 nm an extremely thin and amorphous layer was depicted. Oriented kaolinite films were obtained by MAPLE even at 5 wt.% kaolinite in the target.

7.
Molecules ; 26(20)2021 Oct 14.
Article in English | MEDLINE | ID: mdl-34684773

ABSTRACT

Mechanical activation and mechanochemical reactions are the subjects of mechanochemistry, a special branch of chemistry studied intensively since the 19th century. Herein, we comparably describe two synthesis methods used to obtain the following layered double hydroxide doped with cerium, Mg3Al0.75Ce0.25(OH)8(CO3)0.5·2H2O: the mechanochemical route and the co-precipitation method, respectively. The influence of the preparation method on the physico-chemical properties as determined by multiple techniques such as XRD, SEM, EDS, XPS, DRIFT, RAMAN, DR-UV-VIS, basicity, acidity, real/bulk densities, and BET measurements was also analyzed. The obtained samples, abbreviated HTCe-PP (prepared by co-precipitation) and HTCe-MC (prepared by mechanochemical method), and their corresponding mixed oxides, Ce-PP (resulting from HTCe-PP) and Ce-MC (resulting from HTCe-MC), were used as base catalysts in the self-condensation reaction of cyclohexanone and two Claisen-Schmidt condensations, which involve the reaction between an aromatic aldehyde and a ketone, at different molar ratios to synthesize compounds with significant biologic activity from the flavonoid family, namely chalcone (1,3-diphenyl-2-propen-1-one) and flavone (2-phenyl-4H-1benzoxiran-4-one). The mechanochemical route was shown to have indisputable advantages over the co-precipitation method for both the catalytic activity of the solids and the costs.

8.
Biomolecules ; 11(6)2021 06 17.
Article in English | MEDLINE | ID: mdl-34204372

ABSTRACT

Basal cell carcinoma (BCC) is the most common skin malignancy, which rarely metastasizes but has a great ability to infiltrate and invade the surrounding tissues. One of the molecular players involved in the metastatic process are matrix metalloproteinases (MMPs). MMPs are enzymes that can degrade various components of the extracellular matrix. In the skin, the expression of MMPs is increased in response to various stimuli, including ultraviolet (UV) radiation, one of the main factors involved in the development of BCC. By modulating various processes that are linked to tumor growth, such as invasion and angiogenesis, MMPs have been associated with UV-related carcinogenesis. The sources of MMPs are multiple, as they can be released by both neoplastic and tumor microenvironment cells. Inhibiting the action of MMPs could be a useful therapeutic option in BCC management. In this review that reunites the latest advances in this domain, we discuss the role of MMPs in the pathogenesis and evolution of BCC, as molecules involved in tumor aggressiveness and risk of recurrence, in order to offer a fresh and updated perspective on this field.


Subject(s)
Carcinoma, Basal Cell , Collagenases/metabolism , Neoplasm Proteins/metabolism , Neovascularization, Pathologic , Skin Neoplasms , Tumor Microenvironment/radiation effects , Ultraviolet Rays/adverse effects , Carcinoma, Basal Cell/blood supply , Carcinoma, Basal Cell/enzymology , Carcinoma, Basal Cell/pathology , Humans , Neoplasm Invasiveness , Neovascularization, Pathologic/enzymology , Neovascularization, Pathologic/pathology , Skin Neoplasms/blood supply , Skin Neoplasms/enzymology , Skin Neoplasms/pathology
9.
Materials (Basel) ; 14(11)2021 Jun 01.
Article in English | MEDLINE | ID: mdl-34206068

ABSTRACT

This paper deals with original research in smart leather surface design for the development of multifunctional properties by using multi-walled carbon nanotube (MWCNT)-based nanocomposites. The conductive properties were demonstrated for both sheepskin and bovine leather surfaces for 0.5% MWCNTs in finishing nanocompositions with prospects for new material design intended for flexible electronics or multifunctional leathers. The photocatalytic properties of bovine leather surface treated with 0.5% MWCNTs were shown against an olive oil stain after visible light exposure and were attributed to reactive oxygen species generation and supported by contact angle measurements in dynamic conditions. The volatile organic compounds' decomposition and antibacterial tests confirmed the self-cleaning experimental conclusions. Ultraviolet protection factor had excellent values for leather surfaces treated with multi-walled carbon nanotube and the fastness resistance tests showed improved performance compared to control samples. Scanning electron microscopy with energy dispersive X-ray (SEM-EDX), X-ray photoelectron spectroscopy (XPS), and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy analysis confirmed the influence of different leather surfaces on MWCNT dispersion with an effect on nanoparticle reactivity and efficiency in self-cleaning properties. Multifunctional leather surfaces were designed and demonstrated through MWCNT-based nanocomposite use under conventional finishing conditions.

10.
Nanomaterials (Basel) ; 11(6)2021 May 21.
Article in English | MEDLINE | ID: mdl-34064252

ABSTRACT

Properties such as large surface area, high pore volume, high chemical and thermal stability, and structural flexibility render zeolitic imidazolate frameworks (ZIFs) well-suited materials for gas separation, chemical sensors, and optical and electrical devices. For such applications, film processing is a prerequisite. Herein, matrix-assisted pulsed laser evaporation (MAPLE) was successfully used as a single-step deposition process to fabricate ZIF-8 films. By correlating laser fluency and controlling the specific transfer of lab-synthesized ZIF-8, films with user-controlled physical and chemical properties were obtained. Films' characteristics were evaluated by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The analysis showed that frameworks of ZIF-8 can be deposited successfully and controllably to yield polycrystalline films. The deposited films maintained the integrity of the individual ZIF-8 framework, while undergoing minor crystalline and surface chemistry changes. No significant changes in particle size were observed. Our study demonstrated control over both the MAPLE deposition conditions and the outcome, as well as the suitability of the listed deposition method to create composite architectures that could potentially be used in applications ranging from selective membranes to gas sensors.

11.
Exp Ther Med ; 21(5): 532, 2021 May.
Article in English | MEDLINE | ID: mdl-33815605

ABSTRACT

Skin endometriosis is a rare disease with variable clinical and histopathological characteristics that depend on hormonal stimuli. The skin is not a common location, as most cases of endometriosis involve pelvic sites, such as the ovaries, peritoneum and bowel. However, the most common extrapelvic site affected is the abdominal wall and this location of the disease is frequently associated with obstetric and gynecologic surgery. Here we report a case of skin endometriosis emerged as a painful subcutaneous nodule located near to the left side of an obstetrical surgery procedure scar. The patient affected was a woman in her reproductive age, with a history of right ovary endometriotic cyst laparoscopically removed and histologically confirmed as a primary endometriosis. Dermatologists should be aware of this condition in any woman with a painful lump located in the proximity of a pelvic surgery-induced scar. Its non-specific clinical appearance may confuse the clinician and may delay the diagnosis and management.

12.
Sci Transl Med ; 13(590)2021 04 21.
Article in English | MEDLINE | ID: mdl-33883273

ABSTRACT

Fetal lung underdevelopment, also known as pulmonary hypoplasia, is characterized by decreased lung growth and maturation. The most common birth defect found in babies with pulmonary hypoplasia is congenital diaphragmatic hernia (CDH). Despite research and clinical advances, babies with CDH still have high morbidity and mortality rates, which are directly related to the severity of lung underdevelopment. To date, there is no effective treatment that promotes fetal lung growth and maturation. Here, we describe a stem cell-based approach in rodents that enhances fetal lung development via the administration of extracellular vesicles (EVs) derived from amniotic fluid stem cells (AFSCs). Using fetal rodent models of pulmonary hypoplasia (primary epithelial cells, organoids, explants, and in vivo), we demonstrated that AFSC-EV administration promoted branching morphogenesis and alveolarization, rescued tissue homeostasis, and stimulated epithelial cell and fibroblast differentiation. We confirmed this regenerative ability in in vitro models of lung injury using human material, where human AFSC-EVs obtained following good manufacturing practices restored pulmonary epithelial homeostasis. Investigating EV mechanism of action, we found that AFSC-EV beneficial effects were exerted via the release of RNA cargo. MicroRNAs regulating the expression of genes involved in lung development, such as the miR17-92 cluster and its paralogs, were highly enriched in AFSC-EVs and were increased in AFSC-EV-treated primary lung epithelial cells compared to untreated cells. Our findings suggest that AFSC-EVs hold regenerative ability for underdeveloped fetal lungs, demonstrating potential for therapeutic application in patients with pulmonary hypoplasia.


Subject(s)
Amniotic Fluid , Extracellular Vesicles , Lung/embryology , Stem Cells , Animals , Humans , Rodentia
13.
Molecules ; 25(18)2020 Sep 08.
Article in English | MEDLINE | ID: mdl-32911637

ABSTRACT

We report on the investigation of stearic acid-layered double hydroxide (LDH) composite films, with controlled wettability capabilities, deposited by a combined pulsed laser deposition (PLD)-matrix-assisted pulsed laser evaporation (MAPLE) system. Two pulsed lasers working in IR or UV were used for experiments, allowing the use of proper deposition parameters (wavelength, laser fluence, repetition rate) for each organic and inorganic component material. We have studied the time stability and wettability properties of the films and we have seen that the morphology of the surface has a low effect on the wettability of the surfaces. The obtained composite films consist in stearic acid aggregates in LDH structure, exhibiting a shift to hydrophobicity after 36 months of storage.


Subject(s)
Hydroxides/chemistry , Lasers , Models, Theoretical , Stearic Acids/chemistry , Spectroscopy, Fourier Transform Infrared
14.
Sci Rep ; 10(1): 1755, 2020 02 04.
Article in English | MEDLINE | ID: mdl-32020001

ABSTRACT

Insect CAPA neuropeptides are homologs of mammalian neuromedin U and are known to influence ion and water balance by regulating the activity of the Malpighian 'renal' tubules (MTs). Several diuretic hormones are known to increase primary fluid and ion secretion by insect MTs and, in adult female mosquitoes, a calcitonin-related peptide (DH31) called mosquito natriuretic peptide, increases sodium secretion to compensate for the excess salt load acquired during blood-feeding. An endogenous mosquito anti-diuretic hormone was recently described, having potent inhibitory activity against select diuretic hormones, including DH31. Herein, we functionally deorphanized, both in vitro and in vivo, a mosquito anti-diuretic hormone receptor (AedaeADHr) with expression analysis indicating highest enrichment in the MTs where it is localized within principal cells. Characterization using a heterologous in vitro system demonstrated the receptor was highly sensitive to mosquito CAPA neuropeptides while in vivo, AedaeADHr knockdown abolished CAPA-induced anti-diuretic control of DH31-stimulated MTs. CAPA neuropeptides are produced within a pair of neurosecretory cells in each of the abdominal ganglia, whose axonal projections innervate the abdominal neurohaemal organs, where these neurohormones are released into circulation. Lastly, pharmacological inhibition of nitric oxide synthase (NOS) and protein kinase G (PKG) signaling eliminated anti-diuretic activity of CAPA, highlighting the role of the second messenger cGMP and NOS/PKG in this anti-diuretic signaling pathway.


Subject(s)
Aedes/metabolism , Antidiuretic Agents/metabolism , Insect Proteins/metabolism , Mosquito Vectors/metabolism , Neuropeptides/metabolism , Signal Transduction/physiology , Animals , Cyclic GMP/metabolism , Cyclic GMP-Dependent Protein Kinases/metabolism , Disease Vectors , Humans , Malpighian Tubules/metabolism , Nitric Oxide Synthase/metabolism , Second Messenger Systems/physiology
15.
Arch Dis Child Fetal Neonatal Ed ; 105(4): 432-439, 2020 Jul.
Article in English | MEDLINE | ID: mdl-31801792

ABSTRACT

AIM: To determine (1) the incidence of neurodevelopmental impairment (NDI) in necrotising enterocolitis (NEC), (2) the impact of NEC severity on NDI in these babies and (3) the cerebral lesions found in babies with NEC. METHODS: Systematic review: three independent investigators searched for studies reporting infants with NDI and a history of NEC (PubMed, Medline, Cochrane Collaboration, Scopus). Meta-analysis: using RevMan V.5.3, we compared NDI incidence and type of cerebral lesions between NEC infants versus preterm infants and infants with medical vs surgical NEC. RESULTS: Of 10 674 abstracts screened, 203 full-text articles were examined. In 31 studies (n=2403 infants with NEC), NDI incidence was 40% (IQR 28%-64%) and was higher in infants with surgically treated NEC (43%) compared with medically managed NEC (27%, p<0.00001). The most common NDI in NEC was cerebral palsy (18%). Cerebral lesions: intraventricular haemorrhage (IVH) was more common in NEC babies (26%) compared with preterm infants (18%; p<0.0001). There was no difference in IVH incidence between infants with surgical NEC (25%) and those treated medically (20%; p=0.4). The incidence of periventricular leukomalacia (PVL) was significantly increased in infants with NEC (11%) compared with preterm infants (5%; p<0.00001). CONCLUSIONS: This study shows that a large proportion of NEC survivors has NDI. NEC babies are at higher risk of developing IVH and/or PVL than babies with prematurity alone. The degree of NDI seems to correlate to the severity of gut damage, with a worse status in infants with surgical NEC compared with those with medical NEC. TRIAL REGISTRATION NUMBER: CRD42019120522.


Subject(s)
Enterocolitis, Necrotizing/complications , Neurodevelopmental Disorders/epidemiology , Cerebellum/pathology , Humans , Incidence , Infant, Newborn , Neurodevelopmental Disorders/etiology , Neurodevelopmental Disorders/pathology
16.
Pharmaceutics ; 11(8)2019 Aug 11.
Article in English | MEDLINE | ID: mdl-31405234

ABSTRACT

Despite advances in intensive care, several neonatal conditions typically due to prematurity affect vital organs and are associated with high mortality and long-term morbidities. Current treatment strategies for these babies are only partially successful or are effective only in selected patients. Regenerative medicine has been shown to be a promising option for these conditions at an experimental level, but still warrants further exploration for the development of optimal treatment. Although stem cell-based therapy has emerged as a treatment option, studies have shown that it is associated with potential risks and hazards, especially in the fragile population of babies. Recently, extracellular vesicles (EVs) have emerged as an attractive therapeutic alternative that holds great regenerative potential and is cell-free. EVs are nanosized particles endogenously produced by cells that mediate intercellular communication through the transfer of their cargo. Currently, EVs are garnering considerable attention as they are the key effectors of stem cell paracrine signaling and can epigenetically regulate target cell genes through the release of RNA species, such as microRNA. Herein, we review the emerging literature on the therapeutic potential of EVs derived from different sources for the treatment of neonatal conditions that affect the brain, retinas, spine, lungs, and intestines and discuss the challenges for the translation of EVs into clinical practice.

17.
J Phys Chem B ; 118(46): 13290-9, 2014 Nov 20.
Article in English | MEDLINE | ID: mdl-25346998

ABSTRACT

The ability of matrix-assisted pulsed laser evaporation (MAPLE) technique to transfer and deposit high-quality thin organic, bioorganic, and composite films with minimum chemical modification of the target material has been utilized in numerous applications. One of the outstanding problems in MAPLE film deposition, however, is the presence of residual solvent (matrix) codeposited with the polymer material and adversely affecting the quality of the deposited films. In this work, we investigate the possibility of alleviating this problem by reducing the amount of matrix in the target. A series of coarse-grained molecular dynamics simulations are performed for a model lysozyme-water system, where the water serves the role of volatile "matrix" that drives the ejection of the biomolecules. The simulations reveal a remarkable ability of a small (5-10 wt %) amount of matrix to cause the ejection of intact bioorganic molecules. The results obtained for different laser fluences and water concentrations are used to establish a "processing map" of the regimes of molecular ejection in matrix-assisted pulsed laser deposition. The computational predictions are supported by the experimental observation of the ejection of intact lysozyme molecules from pressed lysozyme targets containing small amounts of residual water. The results of this study suggest a new approach for deposition of thin films of bioorganic molecules with minimum chemical modification of the molecular structure and minimum involvement of solvent into the deposition process.


Subject(s)
Molecular Dynamics Simulation , Muramidase/metabolism , Muramidase/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Thermogravimetry , Water/chemistry , Water/metabolism
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