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1.
Oral Dis ; 29(8): 3268-3277, 2023 Nov.
Article in English | MEDLINE | ID: mdl-35921211

ABSTRACT

OBJECTIVE: To evaluate the relation between the expression of PD-1, PD-L1, CD3, CD8, Foxp3 and clinicopathological features in patients with oral leukoplakia (OLK) and oral squamous cell carcinomas (OSCC) as well as the malignant outcome in OLK patients, and to study the effect of PD-1 and PD-L1 on immune microenvironment in the progression of oral carcinogenesis. METHODS: We evaluated the expression of PD-1/PD-L1 and composition of CD3+ , CD8+ and Foxp3+ T lymphocytes in OLK and OSCC samples by immunohistochemical (IHC) staining and analyzed their relation with clinical information and malignant transformation in OLK patients. RESULTS: IHC staining demonstrated that the expression of PD-1 was significantly increased in the high-grade OLK group than in the low-grade OLK group, while PD-L1 was detected mainly in OSCC. The expression of CD3, CD8, and Foxp3 was found higher in the high-grade OLK group than in the low-grade OLK group, and the Foxp3+ cells were found more in the OSCC group than in the high-grade OLK group. PD-1 was significantly correlated with CD3 (p < 0.05, R = 0.52), CD8 (p < 0.05, R = 0.46), and Foxp3 (p < 0.05, R = 0.46), and the low PD-1-expression group showed a better malignant-free survival than high PD-1 expression group in the OLK (p < 0.05). CONCLUSION: The PD-1/PD-L1 may induce immune suppression in OLK and accelerate the progress of malignant transformation.


Subject(s)
Carcinoma, Squamous Cell , Head and Neck Neoplasms , Mouth Neoplasms , Humans , Mouth Neoplasms/pathology , Squamous Cell Carcinoma of Head and Neck , Carcinoma, Squamous Cell/pathology , Programmed Cell Death 1 Receptor , B7-H1 Antigen , Leukoplakia, Oral/pathology , Cell Transformation, Neoplastic , Forkhead Transcription Factors , Tumor Microenvironment
2.
Front Endocrinol (Lausanne) ; 12: 690255, 2021.
Article in English | MEDLINE | ID: mdl-34413829

ABSTRACT

The human endometrium plays a vital role in providing the site for embryo implantation and maintaining the normal development and survival of the embryo. Recent studies have shown that stress is a common factor for the development of unexplained reproductive disorders. The nonreceptive endometrium and disturbed early maternal-fetal interaction might lead to infertility including the repeated embryo implantation failure and recurrent spontaneous abortion, or late pregnancy complications, thereby affecting the quality of life as well as the psychological status of the affected individuals. Additionally, psychological stress might also adversely affect female reproductive health. In recent years, several basic and clinical studies have tried to investigate the harm caused by psychological stress to reproductive health, however, the mechanism is still unclear. Here, we review the relationship between psychological stress and endometrial dysfunction, and its consequent effects on female infertility to provide new insights for clinical therapeutic interventions in the future.


Subject(s)
Embryo Implantation/physiology , Endometrium/physiopathology , Infertility, Female/complications , Stress, Psychological/complications , Uterine Diseases/complications , Female , Humans , Infertility, Female/physiopathology , Pregnancy , Quality of Life , Stress, Psychological/physiopathology , Uterine Diseases/physiopathology
3.
Asian J Androl ; 22(1): 79-87, 2020.
Article in English | MEDLINE | ID: mdl-31210146

ABSTRACT

The transition from spermatogonia to spermatocytes and the initiation of meiosis are key steps in spermatogenesis and are precisely regulated by a plethora of proteins. However, the underlying molecular mechanism remains largely unknown. Here, we report that Src homology domain tyrosine phosphatase 2 (Shp2; encoded by the protein tyrosine phosphatase, nonreceptor type 11 [Ptpn11] gene) is abundant in spermatogonia but markedly decreases in meiotic spermatocytes. Conditional knockout of Shp2 in spermatogonia in mice using stimulated by retinoic acid gene 8 (Stra8)-cre enhanced spermatogonial differentiation and disturbed the meiotic process. Depletion of Shp2 in spermatogonia caused many meiotic spermatocytes to die; moreover, the surviving spermatocytes reached the leptotene stage early at postnatal day 9 (PN9) and the pachytene stage at PN11-13. In preleptotene spermatocytes, Shp2 deletion disrupted the expression of meiotic genes, such as disrupted meiotic cDNA 1 (Dmc1), DNA repair recombinase rad51 (Rad51), and structural maintenance of chromosome 3 (Smc3), and these deficiencies interrupted spermatocyte meiosis. In GC-1 cells cultured in vitro, Shp2 knockdown suppressed the retinoic acid (RA)-induced phosphorylation of extracellular-regulated protein kinase (Erk) and protein kinase B (Akt/PKB) and the expression of target genes such as synaptonemal complex protein 3 (Sycp3) and Dmc1. Together, these data suggest that Shp2 plays a crucial role in spermatogenesis by governing the transition from spermatogonia to spermatocytes and by mediating meiotic progression through regulating gene transcription, thus providing a potential treatment target for male infertility.


Subject(s)
Meiosis/genetics , Protein Tyrosine Phosphatase, Non-Receptor Type 11/genetics , Spermatocytes/metabolism , Spermatogenesis/genetics , Spermatogonia/metabolism , Animals , Cell Cycle Proteins/genetics , Cell Line , Cell Survival , Chondroitin Sulfate Proteoglycans/genetics , Chromosomal Proteins, Non-Histone/genetics , Gene Expression Regulation , Gene Knockdown Techniques , Infertility, Male , Male , Mice , Mice, Knockout , Mice, Transgenic , Phosphate-Binding Proteins/genetics , Rad51 Recombinase/genetics , Real-Time Polymerase Chain Reaction , Spermatocytes/cytology , Spermatogonia/cytology
4.
Asian Journal of Andrology ; (6): 79-87, 2020.
Article in English | WPRIM (Western Pacific) | ID: wpr-1009754

ABSTRACT

The transition from spermatogonia to spermatocytes and the initiation of meiosis are key steps in spermatogenesis and are precisely regulated by a plethora of proteins. However, the underlying molecular mechanism remains largely unknown. Here, we report that Src homology domain tyrosine phosphatase 2 (Shp2; encoded by the protein tyrosine phosphatase, nonreceptor type 11 [Ptpn11] gene) is abundant in spermatogonia but markedly decreases in meiotic spermatocytes. Conditional knockout of Shp2 in spermatogonia in mice using stimulated by retinoic acid gene 8 (Stra8)-cre enhanced spermatogonial differentiation and disturbed the meiotic process. Depletion of Shp2 in spermatogonia caused many meiotic spermatocytes to die; moreover, the surviving spermatocytes reached the leptotene stage early at postnatal day 9 (PN9) and the pachytene stage at PN11-13. In preleptotene spermatocytes, Shp2 deletion disrupted the expression of meiotic genes, such as disrupted meiotic cDNA 1 (Dmc1), DNA repair recombinase rad51 (Rad51), and structural maintenance of chromosome 3 (Smc3), and these deficiencies interrupted spermatocyte meiosis. In GC-1 cells cultured in vitro, Shp2 knockdown suppressed the retinoic acid (RA)-induced phosphorylation of extracellular-regulated protein kinase (Erk) and protein kinase B (Akt/PKB) and the expression of target genes such as synaptonemal complex protein 3 (Sycp3) and Dmc1. Together, these data suggest that Shp2 plays a crucial role in spermatogenesis by governing the transition from spermatogonia to spermatocytes and by mediating meiotic progression through regulating gene transcription, thus providing a potential treatment target for male infertility.


Subject(s)
Animals , Male , Mice , Cell Cycle Proteins/genetics , Cell Line , Cell Survival , Chondroitin Sulfate Proteoglycans/genetics , Chromosomal Proteins, Non-Histone/genetics , Gene Expression Regulation , Gene Knockdown Techniques , Infertility, Male , Meiosis/genetics , Mice, Knockout , Mice, Transgenic , Phosphate-Binding Proteins/genetics , Protein Tyrosine Phosphatase, Non-Receptor Type 11/genetics , Rad51 Recombinase/genetics , Real-Time Polymerase Chain Reaction , Spermatocytes/metabolism , Spermatogenesis/genetics , Spermatogonia/metabolism
5.
Am J Cancer Res ; 9(12): 2599-2617, 2019.
Article in English | MEDLINE | ID: mdl-31911849

ABSTRACT

Inflammation is closely related to oral squamous cell carcinoma (OSCC). However, its mechanism is still obscure. Toll-like receptor 2 (TLR2) plays an important role in oral chronic inflammatory diseases, but the role of TLR2 in OSCC is unclear. Here, we investigated the expression of TLR2 expression in OSCCs and examined the potential role of TLR2 in OSCC through its association with clinicopathological features and patient outcome. We used 4-nitroquinoline 1-oxide (4-NQO) to induce a tongue cancer model in TLR2-/- and wild type (WT) mice. Histological and clinical results both indicated that TLR2 played a protective role in oral tumorigenesis. The results of a cytometric bead array (CBA) indicated that TLR2 deficiency resulted in Th1 and Th2 cytokine abnormalities, especially Th2 abnormalities. Immunohistochemistry also showed that TLR2 deficiency increases the number of tongue-infiltrating M2 macrophages. Overall, our results demonstrated that TLR2 plays an important role in the prevention of oral tumorigenesis and affects the levels of Th2 cytokines and tongue-infiltrating M2 macrophages; therefore, it may be used to prevent the development of oral cancer.

6.
Clin Genet ; 95(2): 277-286, 2019 02.
Article in English | MEDLINE | ID: mdl-30298696

ABSTRACT

The majority of men with defects in spermatogenesis remain undiagnosed. Acephalic spermatozoa is one of the diseases causing primary infertility. However, the causes underlying over half of affected cases remain unclear. Here, we report by whole-exome sequencing the identification of homozygous and compound heterozygous truncating mutations in PMFBP1 of two unrelated individuals with acephalic spermatozoa. PMFBP1 was highly and specifically expressed in human and mouse testis. Furthermore, immunofluorescence staining in sperm from a normal control showed that PMFBP1 localizes to the head-flagella junction region, and the absence of PMFBP1 was confirmed in patients harboring PMFBP1 mutations. In addition, we generated Pmfbp1 knock-out (KO) mice, which we found recapitulate the acephalic sperm phenotype. Label-free quantitative proteomic analysis of testicular sperm from Pmfbp1 KO and control mice showed 124 and 35 proteins, respectively, increased or decreased in sperm from KO mice compared to that found in control mice. Gene ontology analysis indicates that the biological process of Golgi vesicle transport was the most highly enriched in differentially expressed proteins, indicating process defects related to Golgi complex function may disturb formation of the head-neck junction. Collectively, our data indicate that PMFBP1 is necessary for sperm morphology in both humans and mice, and that biallelic truncating mutations in PMFBP1 cause acephalic spermatozoa.


Subject(s)
Alleles , Cytoskeletal Proteins/genetics , Genetic Association Studies , Genetic Predisposition to Disease , Mutation , Teratozoospermia/diagnosis , Teratozoospermia/genetics , Animals , DNA Mutational Analysis , Disease Models, Animal , Homozygote , Humans , Male , Mice , Pedigree , Proteome , Semen Analysis , Spermatozoa/metabolism , Exome Sequencing
7.
Journal of Forensic Medicine ; (6): 285-288, 2019.
Article in English | WPRIM (Western Pacific) | ID: wpr-985008

ABSTRACT

Objective To discuss the methods and strategies to identify the causes of dependents' deaths, as well as provide the experiences that can be used for reference and scientific basis for the forensic identification of the potentially growing deaths of the same kind in the future. Methods The 13 cases concerning death of dependents accepted by Sun Yat-sen University Forensic Center were collected, and the basic information of the dependents were statistically described. The nutritional status, environmental condition and medical care condition were evaluated according to dietary energy, living space, environment and medical treatment condition. Results Among the 13 dependents, there were 11 males and 2 females, with the oldest 74 and the youngest 9 and dwelling time was from 0.4 to 5.6 years. Forensic pathological examination showed that 13 dependents had infectious diseases and 11 were severely dystrophic. There were no fatal mechanical injuries or poisoning in dependents. Molecular pathological screening of 4 cases revealed no pathogenic variants of sudden death susceptible genes. The poor status of the diet, nutrition, living environment and medical care of these dependents were discovered. The direct cause of death of all 13 dependents was identified to be disease. The lack of nutrition, poor living environment and lack of medical care were thought to play a dominant role in causing the deaths of 12 dependants. Conclusion The death identification should follow the judicial procedure. In identification of the causes of death and analysis of the proportion of the affecting factors resulting in death, all factors, including nutrition,environment, medical care, injury and diseases, need to be considered.


Subject(s)
Female , Humans , Male , Cause of Death , Death, Sudden
8.
Diabetes Res Clin Pract ; 138: 75-80, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29408705

ABSTRACT

AIMS: Although Hyperbaric oxygen therapy (HyperBOT) attract our attention successfully these days, it is still full of controversy on the treatment of acute stroke. The aim of this study is to assess the potential long-term neurological consequences and safety of using HyperBOT on intracerebral hemorrhage (ICH) in the diabetics. METHODS: In this prospective, randomized controlled trial, 79 diabetes patients suffering from acute ICH were randomized to treat for 60 min in a monoplace hyperbaric chamber pressurized with pure oxygen to 2.5-atm absolute (ATA) in the HyperBOT group or 1.5 ATA in the normobaric oxygen therapy (NormBOT) group, which was performed as control. Both short-term and long-term neurological consequences were studied and compared in each group on National Institutes of Health Stroke Scale [NIHSS], Barthel Index, modified Rankin Scale [mRS] and Glasgow Outcome Scale [GOS]. The related complications or side-events of all patients were recorded as well at the final follow-up of six months after onset. RESULTS: No distinct difference was observed between each group at one month follow-up. However, in the long-term follow-up of six months, a higher frequency of patients in the HyperBOT group resulted into good outcome with a relative high neurological consequence compared with the NormBOT group (Barthel Index: 85.1% versus 65.6%, P = 0.080; mRS: 89.4% versus 68.8%, P = 0.045; GOS: 83.0% versus 62.5%, P = 0.073; NIHSS: 80.9% versus 56.2%, P = 0.035). CONCLUSIONS: Early HyperBOT was found to be safe and effective with regards to the long-term neurological outcome of diabetic patients suffering from ICH.


Subject(s)
Cerebral Hemorrhage/therapy , Diabetes Complications/therapy , Hyperbaric Oxygenation/methods , Stroke/therapy , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Prospective Studies , Treatment Outcome
9.
Animal Model Exp Med ; 1(1): 14-22, 2018 Mar.
Article in English | MEDLINE | ID: mdl-30891542

ABSTRACT

The proper development of uterus to a state of receptivity and the attainment of implantation competency for blastocyst are 2 indispensable aspects for implantation, which is considered to be a critical event for successful pregnancy. Like many developmental processes, a large number of transcription factors, such as homeobox genes, have been shown to orchestrate this complicated but highly organized physiological process during implantation. In this review, we focus on progress in studies of the role of homeobox genes, especially the Hox and Msx gene families, during implantation, together with subsequent development of post-implantation uterus and related reproductive defects in both mouse models and humans, that have led to better understanding of how implantation is precisely regulated and provide new insights into infertility.

10.
PLoS One ; 12(8): e0183570, 2017.
Article in English | MEDLINE | ID: mdl-28817692

ABSTRACT

This paper proposes a new measure for recommendation through integrating Triangle and Jaccard similarities. The Triangle similarity considers both the length and the angle of rating vectors between them, while the Jaccard similarity considers non co-rating users. We compare the new similarity measure with eight state-of-the-art ones on four popular datasets under the leave-one-out scenario. Results show that the new measure outperforms all the counterparts in terms of the mean absolute error and the root mean square error.


Subject(s)
Algorithms , Models, Theoretical
11.
J Biomed Res ; 31(4): 333-343, 2017 Jul 13.
Article in English | MEDLINE | ID: mdl-28808205

ABSTRACT

Streptococcus mutans is a primary etiological agent of dental caries. Farnesol, as a potential antimicrobial agent, inhibits the development ofS. mutans biofilm. In this study, we hypothesized that farnesol inhibits caries development in vitro and interferes with biofilm formation by regulating virulence-associated gene expression. The inhibitory effects of farnesol to S. mutans biofilms on enamel surfaces were investigated by determining micro-hardness and calcium measurements. Additionally, the morphological changes ofS. mutans biofilms were compared using field emission scanning electron microscopy and confocal laser scanning microscopy, and the vitality and oxygen sensitivity ofS. mutans biofilms were compared using MTT assays. To investigate the molecular mechanisms of farnesol's effects, expressions of possible target genesluxS, brpA, ffh, recA, nth, and smx were analyzed using reverse-transcription polymerase chain reaction (PCR) and quantitative PCR. Farnesol-treated groups exhibited significantly higher micro-hardness on the enamel surface and lower calcium concentration of the supernatants as compared to the-untreated control. Microscopy revealed that a thinner film with less extracellular matrix formed in the farnesol-treated groups. As compared to the-untreated control, farnesol inhibited biofilm formation by 26.4% with 500 µmol/L and by 37.1% with 1,000 µmol/L (P<0.05). Last, decreased transcription levels of luxS, brpA, ffh, recA, nth, and smx genes were expressed in farnesol-treated biofilms. In vitrofarnesol inhibits caries development and S. mutans biofilm formation. The regulation of luxS, brpA, ffh, recA, nth, and smx genes may contribute to the inhibitory effects of farnesol.

13.
Chem Rev ; 117(11): 7331-7376, 2017 Jun 14.
Article in English | MEDLINE | ID: mdl-28520419

ABSTRACT

After three decades of developments, single particle tracking (SPT) has become a powerful tool to interrogate dynamics in a range of materials including live cells and novel catalytic supports because of its ability to reveal dynamics in the structure-function relationships underlying the heterogeneous nature of such systems. In this review, we summarize the algorithms behind, and practical applications of, SPT. We first cover the theoretical background including particle identification, localization, and trajectory reconstruction. General instrumentation and recent developments to achieve two- and three-dimensional subdiffraction localization and SPT are discussed. We then highlight some applications of SPT to study various biological and synthetic materials systems. Finally, we provide our perspective regarding several directions for future advancements in the theory and application of SPT.


Subject(s)
Algorithms , Single Molecule Imaging , Biophysical Phenomena , Microscopy, Fluorescence
14.
Neuropsychiatr Dis Treat ; 13: 421-426, 2017.
Article in English | MEDLINE | ID: mdl-28228657

ABSTRACT

AIM: The role of hyperbaric oxygen therapy (HBOT) in the treatment of acute ischemic stroke is controversial. This study aims to investigate whether the peripheral insulin sensitivity of type 2 diabetes patients suffering from intracerebral hemorrhage can be increased after HBOT. METHODS: Fifty-two type 2 diabetes participants were recruited after being diagnosed with intracerebral hemorrhage in our hospital. Insulin sensitivity was measured by the glucose infusion rate during a hyperinsulinemic euglycemic clamp (80 mU m-2 min-1) at baseline and 10 and 30 days after HBOT sessions. Serum insulin, fasting glucose, and hemoglobin A1C were measured in fasting serum at baseline and after HBOT sessions. In addition, early (∼10 days after onset) and late (1 month after onset) outcomes (National Institutes of Health Stroke Scale, NIHSS scores) and efficacy (changes of NIHSS scores) of HBOT were evaluated. RESULTS: In response to HBOT, the glucose infusion rate was increased by 37.8%±5.76% at 1 month after onset compared with baseline. Reduced serum insulin, fasting glucose, and hemoglobin A1C were observed after HBOT. Both early and late outcomes of the HBOT group were improved compared with baseline (P<0.001). In the control group, there was significant difference only in the late outcome (P<0.05). In the assessment of efficacy, there were statistically significant differences between the groups when comparing changes in NIHSS scores at 10 days and 1 month after onset (P<0.05). CONCLUSION: Peripheral insulin sensitivity was increased following HBOT in type 2 diabetes patients with intracerebral hemorrhage. The HBOT used in this study may be effective for diabetes patients with acute stroke and is a safe and harmless adjunctive treatment.

15.
BMC Med Genet ; 18(1): 19, 2017 Feb 23.
Article in English | MEDLINE | ID: mdl-28231849

ABSTRACT

BACKGROUND: Peutz-Jeghers syndrome (PJS) is a rare disorder characterized by multiple gastrointestinal hamartomatous polyps and mucocutaneous pigmentation. STK11 has been identified as a causative gene for this disease. CASE PRESENTATION: Herein we report a Chinese Han kindred with PJS. Onset for the PJS signs in three of the patients was rarely as early as at birth. We identified a novel heterozygous mutation (c.440_441delGT, p.Arg147Leufs*15) in the gene STK11, causing a short frameshift followed by a deletion of 63% of the amino acids in the STK protein. This mutation co-segregated with the PJS phenotype, and was absent in two hundred of unrelated ethnicity-matched controls. The mutation led to expression decrease of unaffected STK11 protein in patients than in controls, as well in PJ polyps than in circulating leucocytes from the patients. Phosphorylation levels of the downstream kinase AMPKα altered according with the expression of STK11. These results indicated the possibility that haploinsufficiency and epigenetic reduction of STK11 contributed to the pathogenesis of the disease. CONCLUSION: This study identifies a novel mutation in the pathogenic gene STK11 leading to PJS.


Subject(s)
Germ-Line Mutation , Peutz-Jeghers Syndrome/genetics , Protein Serine-Threonine Kinases/genetics , AMP-Activated Protein Kinase Kinases , Adolescent , Base Sequence , DNA/chemistry , DNA/isolation & purification , DNA/metabolism , Exons , Frameshift Mutation , Heterozygote , Humans , Male , Pedigree , Peutz-Jeghers Syndrome/diagnosis , Peutz-Jeghers Syndrome/pathology , Sequence Analysis, DNA
16.
Neurosci Lett ; 644: 83-86, 2017 03 22.
Article in English | MEDLINE | ID: mdl-28237802

ABSTRACT

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of Neuroscience Letters has learned that text throughout this paper duplicates, or nearly duplicates, text in an earlier paper by others (Rusyniak DE, Kirk MA, May JD, Kao LW, Brizendine EJ, Welch JL, Cordell WH, Alonso RJ; Hyperbaric Oxygen in Acute Ischemic Stroke Trial Pilot Study, Stroke. 2003 Feb;34(2):571-4).

17.
PLoS One ; 12(2): e0171014, 2017.
Article in English | MEDLINE | ID: mdl-28170440

ABSTRACT

A considerable amount of surplus nitrogen (N), which primarily takes the form of nitrate, accumulates in the soil profile after harvesting crops from an intensive production system in the North China Plain. The residual soil nitrate (RSN) is a key factor that is included in the N recommendation algorithm. Quantifying the utilization and losses of RSN is a fundamental necessity for optimizing crop N management, improving N use efficiency, and reducing the impact derived from farmland N losses on the environment. In this study, a 15N-labeling method was introduced to study the fate of the RSN quantitatively during the winter wheat growing season by 15N tracer technique combined with a soil column study. A soil column with a 2 m height was vertically divided into 10 20-cm layers, and the RSN in each layer was individually labeled with a 15N tracer before the wheat was sown. The results indicated that approximately 17.68% of the crop N derived from RSN was located in the 0-2 m soil profile prior to wheat sowing. The wheat recovery proportions of RSN at various layers ranged from 0.21% to 33.46%. The percentages that still remained in the soil profile after the wheat harvest ranged from 47.08% to 75.44%, and 19.46-32.64% of the RSN was unaccounted for. Upward and downward movements in the RSN were observed, and the maximum upward and downward distances were 40 cm and 100 cm, respectively. In general, the 15N-labeling method contributes to a deeper understanding of the fates of the RSN. Considering the low crop recovery of the RSN from deep soil layers, water and N saving practices should be adopted during crop production.


Subject(s)
Nitrates/analysis , Seasons , Soil/chemistry , Triticum/growth & development , China , Crops, Agricultural , Nitrogen/analysis , Triticum/metabolism
18.
J Phys Chem Lett ; 8(1): 299-306, 2017 Jan 05.
Article in English | MEDLINE | ID: mdl-27982600

ABSTRACT

Interactions between fluorophores and plasmonic nanoparticles modify the fluorescence intensity, shape, and position of the observed emission pattern, thus inhibiting efforts to optically super-resolve plasmonic nanoparticles. Herein, we investigate the accuracy of localizing dye fluorescence as a function of the spectral and spatial separations between fluorophores (Alexa 647) and gold nanorods (NRs). The distance at which Alexa 647 interacts with NRs is varied by layer-by-layer polyelectrolyte deposition while the spectral separation is tuned by using NRs with varying localized surface plasmon resonance (LSPR) maxima. For resonantly coupled Alexa 647 and NRs, emission to the far field through the NR plasmon is highly prominent, resulting in underestimation of NR sizes. However, we demonstrate that it is possible to improve the accuracy of the emission localization when both the spectral and spatial separations between Alexa 647 and the LSPR are optimized.

19.
J Phys Chem Lett ; 7(22): 4524-4529, 2016 Nov 17.
Article in English | MEDLINE | ID: mdl-27797527

ABSTRACT

Super-resolution microscopy typically achieves high spatial resolution, but the temporal resolution remains low. We report super temporal-resolved microscopy (STReM) to improve the temporal resolution of 2D super-resolution microscopy by a factor of 20 compared to that of the traditional camera-limited frame rate. This is achieved by rotating a phase mask in the Fourier plane during data acquisition and then recovering the temporal information by fitting the point spread function (PSF) orientations. The feasibility of this technique is verified with both simulated and experimental 2D adsorption/desorption and 2D emitter transport. When STReM is applied to measure protein adsorption at a glass surface, previously unseen dynamics are revealed.

20.
Anal Chem ; 88(20): 9926-9933, 2016 10 18.
Article in English | MEDLINE | ID: mdl-27599237

ABSTRACT

Understanding and controlling protein adsorption on surfaces is critical to a range of biological and materials applications. Kinetic details that provide the equilibrium and nonequilibrium mechanisms are difficult to acquire. In this work, single-molecule fluorescence microscopy was used to study the adsorption of Alexa 555 labeled α-lactalbumin (α-LA) on two chemically identical but morphologically different polymer surfaces: flat and porous nylon-6,6 thin films. The adsorption kinetics of spatially resolved single molecule α-LA binding to nylon films were quantified by a monolayer adsorption model. The surface morphology of the porous nylon-6,6 films increased the number of adsorption sites but decreased the binding affinity compared to the flat films. Such single-molecule based kinetic studies may be extended to various protein-polymer interactions.


Subject(s)
Lactalbumin/chemistry , Nylons/chemistry , Adsorption , Fluorescence , Kinetics , Microscopy, Fluorescence/methods , Porosity , Rhodamines/chemistry , Sulfonic Acids/chemistry , Surface Properties , Thermodynamics
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