Influence of thyroid autoimmunity at various clinical stages of hypothyroidism on the risk of miscarriage before 20 weeks of gestation.

PURPOSE: We aimed to clarify the influence of thyroid autoantibodies at various clinical stages of hypothyroidism on the risk of pregnancy loss before 20 weeks of gestation. METHODS: We enrolled 230 pregnant women with a history of recurrent miscarriage. Detailed clinical history, physical examination, and laboratory testing of thyroid function, antithyroid peroxidase (anti-TPO), and antithyroglobulin (anti-TG) were applied among all participants. RESULTS: Coexisting overt hypothyroidism and positive thyroid autoantibodies quadrupled the risk of miscarriage in women before 20 weeks of gestation (OR 4.04, 95% CI = 2.08-7.96, P < 0.001). Women with subclinical hypothyroidism (OR 1.44, 95% CI = 0.81-2.57, P = 0.132,) or who were euthyroid (OR 1.53, 95% CI = 0.86-2.73, P = 0.094) showed a non-significant risk of miscarriage even with positive thyroid autoantibodies. Thyroid-stimulating hormone (TSH) was positively correlated with the number of miscarriages rather than anti-TPO (P < 0.001 and 0.209, respectively). CONCLUSION: Coexistence of overt hypothyroidism and thyroid autoimmunity was the only significant driver of pregnancy loss before 20 weeks of gestation.

Interstitial Lung Disease in Neonates: A Long Road Is Being Paved.

Background: Interstitial lung disease (ILD) is one of the most difficult conditions in pulmonology due to difficulties in diagnosing, classifying, and treating this condition. They require invasive approaches to diagnose (e.g., lung biopsy), non-applicable methods (e.g., lung function tests in newborns), or potentially non-accessible methods (e.g., genetic testing in not-well-equipped facilities, and several weeks are required for results to be announced). They represent a heterogeneous group of diseases in which the alveolar epithelium, parenchyma, and capillaries of the lungs are damaged, which leads to changes in the pulmonary interstitium, proliferation of connective tissue, and thickening of the alveolar-capillary membranes and alveolar septa. These changes are accompanied by impaired oxygen diffusion, progressive respiratory failure, and radiographic signs of bilateral dissemination. Although adult and child classifications for ILD have evolved over the years, classification for ILD in neonates remains a challenge. Case presentation: Here we discuss ILD in neonates briefly, and report two rare cases of ILD (a male white neonate, two-day-old with fibrosing alveolitis, and another male white neonate, one-day old with desquamative interstitial pneumonitis), with these diagnoses initially thought to be presented only in adulthood. Lung biopsy and histopathological findings of the two neonates have shown mononuclear cells in the alveolar spaces, and thickening of the alveolar walls confirmed the diagnosis of fibrosing alveolitis in one neonate, and desquamation of the large mononuclear cells in the intra-alveolar space in the other neonate, with the diagnosis of desquamative interstitial pneumonitis being confirmed. Interstitial lung disease lacks a consensus guideline on classification and diagnosis in neonates, rendering it one of the greatest challenges to pediatricians and neonatologists with remarkable morbidity and mortality rates. Conclusions: Fibrosing alveolitis and desquamative interstitial pneumonitis (DIP) are not adult-only conditions, although rare in neonates, histopathological examination and clinical practice can confirm the diagnosis. Based on our clinical practice, prenatal and maternal conditions may serve as potential risk factors for developing IDL in neonates, and further studies are needed to prove this hypothesis.

Potential impact of epicardial fat thickness, pentraxin-3, and high-sensitive C-reactive protein on the risk of non-proliferative diabetic retinopathy.

Purpose: We tried to clarify the potential association between systemic inflammatory markers like high-sensitive C-reactive protein (Hs-CRP), pentraxin-3 (PTX3), and epicardial fat thickness (EFT) with the non-proliferative diabetic retinopathy (NPDR) in patients with type 2 diabetes mellitus (T2D). Previous studies dealt with diabetic retinopathy as a whole entity rather than early stages of diabetic retinopathy. Early detection of various determinants of NPDR is prioritized in clinical practice. Methods: A case-control study was conducted at Mansoura University Hospital, included 207 Egyptian subjects divided into 3 groups; 69 diabetic patients without retinopathy, 69 diabetic patients with NPDR, and 69 healthy control subjects. Participants were subjected to clinical history taking, physical examination, and laboratory assessment of Hs-CRP and plasma PTX3. Transthoracic echocardiography was applied to estimate EFT. Results: Hs-CRP, PTX3, and EFT were significantly higher in patients with T2D without retinopathy than control cohort (p = 0.033, p < 0.00 and p < 0.00, respectively). Moreover, patients with NPDR showed significantly higher values of Hs-CRP, PTX3, and EFT than diabetic comparators without retinopathy (p = 0.002, p = 0.012, and p < 0.001, respectively). Although, NPDR was positively correlated with Hs-CRP, PTX3, and EFT (p < 0.001), Hs-CRP was not an independent determinant of NPDR meanwhile, EFT (OR = 1.094, 95%CI: 1.036-1.154, P = 0.001) and PTX3 (OR = 16.145, 95%CI: 1.676-155.551, P = 0.016) were. Conclusion: Plasma pentraxin-3 and epicardial fat thickness showed more significant association with NPDR than high-sensitive C-reactive protein in patients with type 2 diabetes mellitus.

Histological alterations of small intestine and growth performance of broiler chicks after in ovo copper injection at 10 days of embryogenesis period.

This study aimed to assess impacts of early in ovo injection (at 10 days of incubation) of copper (sulfate, acetate, or nanoparticles) on histomorphometric parameters of small intestine and growth performance of post-hatched chicks. Fertile eggs (n = 462) were distributed to seven groups (3 replicates, 22 eggs in each). The first group as a control, the 2nd, 3rd and 4th groups injected with 100 µL deionized water containing 8 µg/egg of Cu (sulfate, acetate and nanoparticles, respectively), and the 5th, 6th and 7th groups injected with 100 µL deionized water containing 16 µg/egg of the same Cu sources above. Results illustrated that in ovo administration of Cu sulfate and Cu acetate significantly improved histological parameters of small intestine parts of newly hatched chicks compared with the control. Cu sulfate and nano-Cu significantly augmented body weight gain compared with the control. In ovo Cu injection showed a nonsignificant improvement in feed conversion ratio. The highest level (16 µg/egg) of different sources was better than the lowest level (8 µg/egg) in most results. In conclusion, it is recommended that in ovo injection of Cu (16 µg/egg) can improve the growth performance (Cu sulfate and nano-Cu) and the small intestine histomorphometry parameters (Cu sulfate and Cu acetate) of broiler chicks.

A glimpse into the black box of celiac disease complications: a case report with a rare presentation.

The purpose of this article is to report a case of celiac disease in a child with uncommon presentation and severe complications, and briefly review recent literature regarding celiac disease complications in children. We describe a case report of celiac disease in a child (to our knowledge, this is the first to be reported in its unique presentation in the Russian Federation) and precisely review its presenting complications with the exiting works of literature. Many cases of celiac disease in children who are not diagnosed and treated properly suffer from a plethora of complications due to malabsorption and concurrent autoimmune reactions that affect mainly but are not limited to the endocrine system. Complications of celiac disease in children should always be suspected, and evidence-based follow-up recommendations should be introduced as soon as possible because the burden of celiac disease complications in children is remarkable.

COVID-19, Acute Lymphoblastic Leukemia, and Down Syndrome: A Short Review and a Case Report.

SARS-CoV-2 which causes COVID-19 has been a great challenge to treat and deal with; despite strict measures that had been implemented by governments and organizations, worrying rates of morbidity and mortality are still being reported. Although available data have expressed that moderate or even mild forms of the disease are expected amongst most pediatrics cases, minimal data are available on the prognosis and the disease's complications on the immunocompromised, especially oncology patients. We report a case of relapsed precursor B-cell acute lymphoblastic leukemia of a child with Down syndrome and COVID-19 and outline the treatment regimen that we used.

Optimism for the Single-stage Transanal Swenson in Neonates.

BACKGROUND: Hirschsprung's disease (HD) has been traditionally treated from infancy onward and different techniques have been used including Swenson, Soave, and Duhamel procedures. The purpose of this study was to evaluate the transanal Swenson's procedure for classical rectosigmoid HD in neonates. PATIENT AND METHODS: This was a prospective study in which neonates diagnosed with HD were recruited from January 2017 to December 2018. Cases with a transition zone proximal to the midsigmoid were excluded. All patients underwent a transanal Swenson's procedure in the neonatal period using a unified protocol. Intraoperative course and postoperative outcomes such as leak, pelvic abscess, soiling, perianal excoriation, stricture, enterocolitis, and constipation were evaluated and all patients were followed for at least 6 months. RESULTS: Twenty-three patients (17 males and 6 females) underwent transanal Swenson's procedure. The mean age was 22 ± 5.7 days. Follow-up ranged from 6 to 30 months. No anastomotic leak, retraction, or prolapse was reported. Mild perianal excoriations occurred early in 9 (39%) cases and all responded to medical treatment and disappeared before 2 months postoperatively. Stricture occurred in 2 (8%) patients, enterocolitis in 3 (13%), and constipation in 3 (13%). CONCLUSION: Transanal Swenson's procedure is feasible and can be performed safely in neonates with rectosigmoid HD with good short-term outcomes. Proper patient selection and standard protocol following fine procedural hall-marks and details are keys for optimal results and patient satisfaction.

Acute abdomen caused by rupture of a torted intra-abdominal testicular mass: Case report.

INTRODUCTION: Cryptorchidism is defined as the absence of one or both testicles from the scrotum, which is considered one of the most common birth defects of male genitalia. Mostly the undescended testes are in the inguinal region, while the intra-abdominal location accounts for only 10 % of the cases. The potential risk of malignant transformation in an undescended testis is approximately 2.5-8 times higher than in scrotal position. Torsion of the cryptorchid testis is a very rare cause of acute abdominal pain with few cases published in literature. CASE PRESENTATION: A 44-year-old male patient presented to the emergency room with acute abdominal pain. General examination revealed relevant tachycardia. Upon abdominal examination there was tenderness and rebound tenderness all over the abdomen, more evident in the lower abdomen. Interestingly, routine examination of the inguino-scrotal region revealed empty right hemi-scrotum despite the patient not being aware. Routine blood tests showed marked anemia Hb: 7.4 g/dl. Urgent pelvi-abdominal U/S showed moderate free intra-abdominal collection in addition to a pelvic mass. CT of the abdomen showed a well-defined heterogenous hypodense mass measuring about 8.5 × 5.5 cm in the pelvis. Urgent exploratory laparotomy was done, and a mass was found to be torted and ruptured. Excision was done and histo-pathological examination revealed testicular mixed germ cell tumor. CONCLUSION: Undescended testis is associated with an increased risk of infertility, testicular cancer and torsion. In any male with undescended testis and intra-abdominal mass; the risk of intra-abdominal testicular tumor should be considered.

A report of two infant cases operated for jejunal duplication cyst associated with malrotation and volvulus.

INTRODUCTION: Both Enteric duplication and intestinal malrotation are concerning causes for intestinal obstruction in the pediatric age group and they very rarely coexist in the same patient. PRESENTATION OF CASES: We present 2 cases of previously healthy children, the first is a 4-month-old infant and the second is a 1.5-year-old boy, both presented with recurrent attacks of bilious vomiting that proved to be due to acute midgut volvulus caused by an enteric duplication cyst associated with intestinal malrotation. DISCUSSION: Enteric duplication and intestinal malrotation are two of the concerning causes of billious vomiting in the pediatric age group. They could be encountered at any level of the alimentary tract from the tongue to the anus. The term malrotation refers to all abnormalities of intestinal position. The coincidence of intestinal malrotation and an enteric duplication cyst (EDC) is very rare and has been described only in a few case reports. CONCLUSION: The concomitance of EDC and intestinal malrotation is extremely rare and should be kept in mind in a child presenting with bilious vomiting especially in a child preoperatively diagnosed with a duplication cyst.

Rare Copy Number Variations and Predictors in Children With Intellectual Disability and Epilepsy.

Introduction: The concurrence of intellectual disability/global developmental delay and epilepsy (ID/GDD-EP) is very common in the pediatric population. The etiologies for both conditions are complex and largely unknown. The predictors of significant copy number variations (CNVs) are known for the cases with ID/GDD, but unknown for those with exclusive ID/GDD-EP. Importantly, the known predictors are largely from the same ethnic group; hence, they lack replication. Purpose: We aimed to determine and investigate the diagnostic yield of CNV tests, new causative CNVs, and the independent predictors of significant CNVs in Chinese children with unexplained ID/GDD-EP. Materials and methods: A total of 100 pediatric patients with unexplained ID/GDD-EP and 1,000 healthy controls were recruited. The American College of Medical Genetics guideline was used to classify the CNVs. Additionally, clinical information was collected and compared between those with significant and non-significant CNVs. Results: Twenty-eight percent of the patients had significant CNVs, 16% had variants of unknown significance, and 56% had non-significant CNVs. In total, 31 CNVs were identified in 28% (28/100) of cases: 25 pathogenic and 6 likely pathogenic. Eighteen known syndromes were diagnosed in 17 cases. Thirteen rare CNVs (8 novel and 5 reported in literature) were identified, of which three spanned dosage-sensitive genes: 19q13.2 deletion (ATP1A3), Xp11.4-p11.3 deletion (CASK), and 6q25.3-q25.3 deletion (ARID1B). By comparing clinical features in patients with significant CNVs against those with non-significant CNVs, a statistically significant association was found between the presence of significant CNVs and speech and language delay for those aged above 2 years and for those with facial malformations, microcephaly, congenital heart disease, fair skin, eye malformations, and mega cisterna magna. Multivariate logistic regression analysis allowed the identification of two independent significant CNV predictors, which are eye malformations and facial malformations. Conclusion: Our study supports the performance of CNV tests in pediatric patients with unexplained ID/GDD-EP, as there is high diagnostic yield, which informs genetic counseling. It adds 13 rare CNVs (8 novel), which can be accountable for both conditions. Moreover, congenital eye and facial malformations are clinical markers that can aid clinicians to understand which patients can benefit from the CNV testing and which will not, thus helping patients to avoid unnecessary and expensive tests.

[PCDH19 gene mutations lead to epilepsy with mental retardation limited to females in 2 cases and literature review].

Epilepsy with mental retardation limited to females (EFMR) is a syndrome characterized by early onset heat-sensitive epilepsy of infancy or early childhood and generally limited to females, which previously reported that the cadherin gene superfamily subtype protocadherin 19 (PCDH19) gene is its pathogenic gene. We retrospectively analyzed the clinical data for 2 cases of EFMR patients with PCDH19 mutation diagnosed by Department of Pediatric Neurology of Xiangya Hospital, Central South University in 2015. Literature on PubMed, OMIM and HGMD relevant to this syndrome was reviewed, and the clinical characteristics were summarized accordingly. The 2 cases are consistent with the typical clinical manifestations of EFMR caused by PCDH19 mutations. Their seizures are heat sensitive, with or without screaming, and expressed in various forms. Cognitive impairment or autism-like performance were often identified in these patients, hematuria metabolic diseases screening was normal, no abnormal MRI imaging of the head, and de novo PCDH19 gene mutations were found in their epilepsy gene chip sequencing. It is noteworthy that this disease is very similar to the clinical manifestations of the Dravet syndrome due to the mutations of the neurotype sodium channel α1 subunit SCN1A. Therefore, in female patients whose clinical manifestations resemble to Dravet syndrome but SCN1A gene test were negative, EFMR with PCDH19 mutation should be taken into consideration. Early PCDH19 gene testingis of great significance because it not only helps clinicians to understand and analyze the prognosis of this disease, but also offers genetic counseling to the parents.

The effect of IL-1ß on synaptophysin expression and electrophysiology of hippocampal neurons through the PI3K/Akt/mTOR signaling pathway in a rat model of mesial temporal lobe epilepsy.

BACKGROUND: The inflammation induced by interleukin-1ß (IL-1ß) is a critical factor in the pathogenesis of mesial temporal lobe epilepsy (MTLE). Synaptophysin (SYN) and other changes, including neuron electrophysiology, participate in the pathophysiological processes of MTLE. Phosphatidylinositol 3-kinase (PI3K)/Akt/ mammalian target of rapamycin (mTOR) signaling pathway may play a critical role in regulating SYN expression and electrophysiology of hippocampal neurons. METHODS: We used lithium-pilocarpine-treated rats as model of human MTLE, detecting epileptic seizures with digital video-EEG, and evaluating the proteins related to the PI3K/Akt/mTOR signaling pathway by western blot (WB). Then, we cultured primary neuron and established a neuronal epilepsy model using Mg2+-free media. Immunocytochemistry and WB were used to investigate SYN expression, and whole-cell current clamp recording techniques were used to detect the electrophysiological properties of cultured neurons. RESULTS: We have demonstrated that IL-1ß can activate the PI3K/Akt/mTOR signaling pathway in primary hippocampal neurons, and we speculate that IL-1ß may affect SYN expression and neuron electrophysiology through PI3K/Akt/mTOR signaling pathway. CONCLUSION: We confirmed that IL-1ß stimulated SYN expression and epileptiform discharges, and that blocking the PI3K/Akt/mTOR pathway alleviated these phenomena. Therefore, activation of the PI3K/Akt/mTOR signaling pathway by IL-1ß contributes to the pathogenesis of MTLE, and modulating this pathway is a promising strategy of study for therapies to prevent or reverse the cellular and molecular mechanisms of epileptogenesis in MTLE.

Unexplained Early Infantile Epileptic Encephalopathy in Han Chinese Children: Next-Generation Sequencing and Phenotype Enriching.

Early Infantile Epileptic Encephalopathy (EIEE) presents shortly after birth with frequent, severe seizures and progressive disturbance of cerebral function. This study was to investigate a cohort of Chinese children with unexplained EIEE, infants with previous genetic diagnoses, causative brain malformations, or inborn errors of metabolism were excluded. We used targeted next-generation sequencing to identify potential pathogenic variants of 308 genes in 68 Han Chinese patients with unexplained EIEE. A filter process was performed to prioritize rare variants of potential functional significance. In all cases where parental testing was accessible, Sanger sequencing confirmed the variants and determined the parental origin. In 15% of patients (n = 10/68), we identified nine de novo pathogenic variants, and one assumed de novo pathogenic variant in the following genes: CDKL5 (n = 2), STXBP1 (n = 2), SCN1A (n = 3), KCNQ2 (n = 2), SCN8A (n = 1), four of the variants are novel variants. In 4% patients (n = 3/68), we identified three likely pathogenic variants; two assumed de novo and one X-linked in the following genes: SCN1A (n = 2) and ARX (n = 1), two of these variants are novel. Variants were assumed de novo when parental testing was not available. Our findings were first reported in Han Chinese patients with unexplained EIEE, enriching the EIEE mutation spectrum bank.

Interleukin-1ß Plays a Pivotal Role via the PI3K/Akt/mTOR Signaling Pathway in the Chronicity of Mesial Temporal Lobe Epilepsy.

OBJECTIVE: Mesial temporal lobe epilepsy (MTLE) is the most common type of refractory epilepsy. It is often associated with hippocampal sclerosis, which is histopathologically characterized by selective neuron loss, mossy fiber sprouting, and synapse reconstruction, and is the primary cause of refractory epilepsy. Its mechanism has not been fully elucidated. Substantial evidence now supports that inflammatory pathways are activated in epilepsy foci. We have confirmed that the interleukin-1ß (IL-1ß) level is involved in the epileptogenesis of MTLE, and we further investigated how it works in its chronicity in this study. METHODS: The MTLE model was induced by pilocarpine, and Western blot and co-immunoprecipitation were used to detect proteins related to the PI3K/Akt/mammalian target of rapamycin (mTOR) signaling pathway in the hippocampi of MTLE rats and MTLE children. Meanwhile, primary hippocampal neurons were cultured and transfected by lentivirus, and the same methods were used to test the related protein expression; fluorescent dye FM4-64 was used to measure synaptic vesicle endocytosis (SVE) of neurons. RESULTS: We revealed that mTOR is continuously activated in the rat MTLE model and children with MTLE, and it correlated with the IL-1ß level. We further proved that IL-1ß activates neurons via the PI3K/Akt/mTOR signaling pathway, accompanied by the upregulation of MAP2 and the enhancement of SVE in hippocampal neurons. CONCLUSION: Our findings suggest that IL-1ß can activate mTOR, followed by activated neurons, which is critical in the pathogenesis of MTLE chronicity. These findings contribute to the understanding of the pathogenesis of MTLE, and targeting inflammation modulators in MTLE may provide new pathways for therapy of refractory epilepsy.

Covalently attached organic monolayers on SiC and SixN4 surfaces: formation using UV light at room temperature.

We describe the formation of alkyl monolayers on silicon carbide (SiC) and silicon-rich silicon nitride (SixN4) surfaces, using UV irradiation in the presence of alkenes. Both the surface preparation and the monolayer attachment were carried out under ambient conditions. The stable coatings obtained in this way were studied by water contact angle measurements, infrared reflection absorption spectroscopy, X-ray reflectivity, and X-ray photoelectron spectroscopy. Besides unfunctionalized 1-alkenes, methyl undec-10-enoate, and 2,2,2-trifluoroethyl undec-10-enoate were also grafted onto both substrates. The resulting ester-terminated surfaces could then be further reacted after hydrolysis using amide chemistry to easily allow the attachment of amine-containing compounds.

Covalent attachment of bent-core mesogens to silicon surfaces.

Two vinyl-terminated bent core-shaped liquid crystalline molecules that exhibit thermotropic antiferroelectric SmCPA phases have been covalently attached onto a hydrogen-terminated silicon(111) surface. The surface attachment was achieved via a mild procedure from a mesitylene solution, using visible light at room temperature. AFM measurements indicate that a smooth monolayer has been formed. The thickness of the monolayer was evaluated with ellipsometry and X-ray reflectivity. Although the molecules differ in length by four carbon atoms, the thickness of the resulting monolayers was the same. The measured thicknesses correspond quite well with the smectic layer thickness in the bulk liquid crystalline material, suggesting a similar self-organization within the monolayer. From attenuated total reflectance infrared (ATR-IR), which clearly shows the C-H and C-O vibrations, a tilt angle of the mesogens is deduced that also corresponds well with the tilt angle in the liquid crystalline state. X-ray photoelectron spectroscopy (XPS) measurements confirm the high quality of the monolayers, with only marginal silicon oxide formation. The elemental composition and amounts of different O and C atoms deduced from the high-resolution XPS correspond very well with the calculated compositions.

One-step photochemical attachment of NHS-terminated monolayers onto silicon surfaces and subsequent functionalization.

N-Hydroxysuccinimide (NHS)-ester-terminated monolayers were covalently attached in one step onto silicon using visible light. This mild photochemical attachment, starting from omega-NHS-functionalized 1-alkenes, yields a clean and flat monolayer-modified silicon surface and allows a mild and rapid functionalization of the surface by substitution of the NHS-ester moieties with amines at room temperature. Using a combination of analytical techniques (infrared reflection absorption spectroscopy (IRRAS), extensive X-ray photoelectron spectroscopy (XPS) in combination with density functional theory calculations of the XPS chemical shifts of the carbon atoms, atomic force microscopy (AFM), and static contact angle measurements), it was shown that the NHS-ester groups were attached fully intact onto the surface. The surface reactivity of the NHS-ester moieties toward amines was qualitatively and quantitatively evaluated via the reaction with para-trifluoromethyl benzylamine and biotin hydrazide.

Covalent attachment of organic monolayers to silicon carbide surfaces.

This work presents the first alkyl monolayers covalently bound on HF-treated silicon carbide surfaces (SiC) through thermal reaction with 1-alkenes. Treatment of SiC with diluted aqueous HF solutions removes the native oxide layer (SiO2) and provides a reactive hydroxyl-covered surface. Very hydrophobic methyl-terminated surfaces (water contact angle theta = 107 degrees ) are obtained on flat SiC, whereas attachment of omega-functionalized 1-alkenes also yields well-defined functionalized surfaces. Infrared reflection absorption spectroscopy, ellipsometry, and X-ray photoelectron spectroscopy measurements are used to characterize the monolayers and show their covalent attachment. The resulting surfaces are shown to be extremely stable under harsh acidic conditions (e.g., no change in theta after 4 h in 2 M HCl at 90 degrees C), while their stability in alkaline conditions (pH = 11, 60 degrees C) also supersedes that of analogous monolayers such as those on Au, Si, and SiO2. These results are very promising for applications involving functionalized silicon carbide.

Self-assembly of high-quality covalently bound organic monolayers onto silicon.

A very mild method has been developed to obtain covalently attached alkyl monolayers from the attachment of 1-alkynes onto hydrogen-terminated silicon surfaces at room temperature in the dark. Apart from being the mildest method reported so far for the preparation of such monolayers, their quality, as indicated by water contact angles, XPS, and infrared spectroscopy, equals within experimental error that of the best reported alkyl monolayers on silicon.

Covalent biofunctionalization of silicon nitride surfaces.

Covalently attached organic monolayers on etched silicon nitride (SixN4; x >/= 3) surfaces were prepared by reaction of SixN4-coated wafers with neat or solutions of 1-alkenes and 1-alkynes in refluxing mesitylene. The surface modification was monitored by measurement of the static water contact angle, XPS, IRRAS, AFM, and ToF-SIMS, and evidence for the formation of Si-C bonds is presented. The etching can be achieved by dilute HF solutions and yields both Si-H and N-H moieties. The resulting etched SixN4 surfaces are functionalized by terminal carboxylic acid groups in either of two ways: (a) via attachment of a 10-undecenoic acid 2,2,2-trifluoroethyl ester (trifluoro ethanol ester) and subsequent thermal acid hydrolysis; (b) through attachment of a photocleavable ester, and subsequent photochemical cleavage, as this would allow photopatterned functionalized SixN4. The carboxylic acids are successfully used for the attachment of oligopeptides (aspartame) and complete proteins using EDC/NHS chemistry. Finally, an amino-terminated organic monolayer can be formed by reaction of HF-treated SixN4 surfaces with a N-(omega-undecylenyl)phthalimide, which yields an amino-terminated surface upon deprotection with hydrazine.