Real-Time Study of the Specific Interactions of Lactoferrin with Mimicked Heparan Sulfate Meshes Using Ordered Porous Layer Interferometry.

Heparan sulfate (HS) meshes within the glycocalyx on cell surfaces have protein recognition ability and have been crucial for gaining insights into vital bioprocesses, such as viral infection, cancer development, and inflammation. The protein recognition ability is determined by the mesh property and compositions of HS, although little attention has been paid to the effect of the mesh property on the recognition. An in-depth specificity study of protein-HS-mesh recognition is essential to illustrate related biological functions. Here, ordered porous layer interferometry is applied to study the interaction behavior between mimicked HS meshes and lactoferrin (LF). Our work aimed at mimicking HS meshes with heparin, a widely used substitute of HS, and analyzing the specific LF-heparin-mesh interaction mechanism by inhibiting the nonspecific interaction in a blended sample. We found that the counterion release-based electrostatic interaction is dominant in the specific LF-heparin-mesh recognition. Furthermore, we detail the contributions of nonspecific and specific interactions to the recognition. We illustrate that the concentrated charge distribution of the proteins appears to be primarily related to this robust, specific recognition.

Development of a Methodology Based on Optical Interferometry for Measuring Fibrinolytic Activity.

Fibrinolytic activity assay is particularly important for the detection, diagnosis, and treatment of cardiovascular disease and the development of fibrinolytic drugs. A novel efficacious strategy for real-time and label-free dynamic detection of fibrinolytic activity based on ordered porous layer interferometry (OPLI) was developed. Fibrin or a mixture of fibrin and plasminogen (Plg) was loaded into the highly ordered silica colloidal crystal (SCC) film scaffold to construct a fibrinolytic response interference layer to measure fibrinolytic activity with different mechanisms of action. Fibrinolytic enzyme-triggered fibrinolysis led to the migration of interference fringes in the interferogram, which could be represented by optical thickness changes (ΔOT) tracked in real time by the OPLI system. The morphology and optical property of the fibrinolytic response interference layer were characterized, and the Plg content in the fibrinolytic response interference layer and experimental parameters of the system were optimized. The method showed adequate sensitivity for the fibrinolytic activity of lumbrokinase and streptokinase, with wide linear ranges of 12-6000 and 10-2000 U/mL, respectively. Compared with the traditional fibrin plate method, it has a lower detection limit and higher linearity. The whole kinetic process of fibrinolysis by these two fibrinolytic drug models was recorded in real time, and the Michaelis constant and apparent kinetic parameters were calculated. Importantly, some other blood proteins were less interfering with this system, and it showed reliability in fibrin activity detection in real whole blood samples. This study established a better and more targeted research method of in vitro fibrinolysis and provided dynamic monitoring data for the analysis of fibrinolytic activity of whole blood.

Fertility history and intentions of married women, China.

Objective: To estimate the proportion of married women in China who intend to become pregnant given the country's pronatalist population policy and to investigate fecundity, with an emphasis on the influence of socioeconomic factors. Methods: A nationally representative survey of 12 815 married women aged 20 to 49 years (mean: 36.8 years) was conducted during 2019 and 2020. All completed questionnaires, 10 115 gave blood samples and 11 710 underwent pelvic ultrasound examination. Fertility intention was the desire or intent to become pregnant combined with engagement in unprotected sexual intercourse. We defined infertility as the failure to achieve pregnancy after 12 months or more of unprotected intercourse. We considered an anti-Müllerian hormone level < 1.1 ng/mL and an antral follicular count < 7 as indicating an abnormal ovarian reserve. Findings: Fertility intentions were reported by 11.9% of women overall but by only 6.1% of current mothers (weighted percentages). Fertility intention was significantly less likely among women in metropolises (odds ratio, OR: 0.38; 95% confidence interval, CI: 0.31-0.45) and those with a higher educational level (OR: 0.74; 95% CI: 0.62-0.88). Overall, 18.0% had experienced infertility at any time and almost 30% had an abnormal ovarian reserve on assessment. An abnormal ovarian reserve and infertility were less likely in women in metropolises (P < 0.05) but more likely in obese women (P < 0.05). Conclusion: The willingness of Chinese married women to give birth remained low, even with relaxation of the one-child policy.

Nanoporous Polystyrene Inverse Opal Materials with Optical Interference Properties for Label-Free Biosensing.

Colloidal crystal nanomaterials have been proven to be valuable substrates for optical-based biosensing due to their ordered macroporous nanostructure and brilliant optical properties. In this work, silica colloidal crystal (SCC) thin films, as well as polystyrene-SCC composite films and inverse opal (IO) polystyrene films fabricated using SCC as templates, are investigated for their application as substrate materials in optical interferometric biosensors. The SCC films formed by the self-assembly of silica colloidal crystals have the most densely packed nano-3D structure, also known as the opal structure. IO films are fabricated by filling the opal pores of SCC with polystyrene and then removing the template, resulting in an interconnected nano-3D ordered macroporous structure, as indicated by the name inverse opal. The performance of the three materials was compared and discussed based on an ordered porous layer interferometry optical platform, focusing on refractive index response, protein adsorption response, and biomolecular interaction response. These results could potentially offer innovative material support for the advancement of label-free optical biosensors, which can be used for more biological/biochemical/biomolecular reaction monitoring studies.

Technically feasible solutions to challenges in preimplantation genetic testing for thalassemia: experiences of multiple centers between 2019 and 2022.

PURPOSE: In clinical practice, the success of preimplantation genetic testing for monogenic diseases (PGT-M) for thalassemia was hindered by the absence of probands, incomplete family members, or failure in detecting embryonic gene mutation sites. This study aimed to address these issues. METHODS: This retrospective study included 342 couples undergoing PGT-M for α- or ß-thalassemia at three reproductive medicine centers from 2019 to 2022. Various methods were used to construct parental haplotypes. A total of 1778 embryos were analyzed and selected for transfer based on chromosomal ploidy and PGT-M results. Follow-up involved amniocentesis results and clinical outcomes. RESULTS: Haplotypes were established using DNA samples from probands or parents, as well as sibling blood samples, single sperm, and affected embryos, achieving an overall success rate was 99.4% (340/342). For α-thalassemia and ß-thalassemia, the concordance between embryo single nucleotide polymorphism (SNP) haplotype analysis results and mutation loci detection results was 93.8% (1011/1078) and 98.2% (538/548), respectively. Multiple annealing and looping-based amplification cycles (MALBAC) showed a higher whole genome amplification success rate than multiple displacement amplification (MDA) (98.8% (1031/1044) vs. 96.2% (703/731), p < 0.001). Amniocentesis confirmed PGT-M outcomes in 100% of cases followed up (99/99). CONCLUSION: This study summarizes feasible solutions to various challenging scenarios encountered in PGT-M for thalassemia, providing valuable insights to enhance success rate of PGT-M in clinical practice.

SRSF2 is required for mRNA splicing during spermatogenesis.

BACKGROUND: RNA splicing plays significant roles in fundamental biological activities. However, our knowledge about the roles of alternative splicing and underlying mechanisms during spermatogenesis is limited. RESULTS: Here, we report that Serine/arginine-rich splicing factor 2 (SRSF2), also known as SC35, plays critical roles in alternative splicing and male reproduction. Male germ cell-specific deletion of Srsf2 by Stra8-Cre caused complete infertility and defective spermatogenesis. Further analyses revealed that deletion of Srsf2 disrupted differentiation and meiosis initiation of spermatogonia. Mechanistically, by combining RNA-seq data with LACE-seq data, we showed that SRSF2 regulatory networks play critical roles in several major events including reproductive development, spermatogenesis, meiotic cell cycle, synapse organization, DNA recombination, chromosome segregation, and male sex differentiation. Furthermore, SRSF2 affected expression and alternative splicing of Stra8, Stag3 and Atr encoding critical factors for spermatogenesis in a direct manner. CONCLUSIONS: Taken together, our results demonstrate that SRSF2 has important functions in spermatogenesis and male fertility by regulating alternative splicing.

Vincristine exposure impairs mouse oocyte quality by inducing spindle defects and early apoptosis.

Vincristine (VCR) is a microtubule-destabilizing chemotherapeutic agent commonly administered for the treatment of cancers in patients, which can induce severe side effects including neurotoxicity. In context of the effects on female fertility, ovarian toxicity has been found in patients and mice model after VCR exposure. However, the influence of VCR exposure on oocyte quality has not been elucidated. We established VCR exposure in vitro and in vivo model. The results indicated in vitro VCR exposure contributed to failure of oocyte maturation through inducing defects in spindle assembly, activation of SAC, oxidative stress, mitochondrial dysfunction, and early apoptosis, which were confirmed by using in vivo exposure model. Moreover, in vivo VCR exposure caused aneuploidy, reduced oocyte-sperm binding ability, and the number of cortical granules in mouse oocyte cortex. Taken together, this study demonstrated that VCR could cause meiotic arrest and poor quality of mouse oocyte.

Chinese experts' consensus guideline on preimplantation genetic testing of monogenic disorders.

Recent developments in molecular biological technologies and genetic diagnostic methods, accompanying with updates of relevant terminologies, have enabled the improvements of new strategies of preimplantation genetic testing for monogenic (single gene) disorders (PGT-M) to prevent the transmission of inherited diseases. However, there has been much in the way of published consensus on PGT-M. To properly regulate the application of PGT-M, Chinese experts in reproductive medicine and genetics have jointly developed this consensus statement. The consensus includes indications for patient selection, genetic and reproductive counseling, informed consent, diagnostic strategies, report generation, interpretation of results and patient follow-ups. This consensus statement serves to assist in establishment of evidence-based clinical and laboratory practices for PGT-M.

Ordered Porous Layer Interferometry for Dynamic Observation of Non-Specific Adsorption Induced by 1-Ethyl-3-(3-(dimethylamino)propyl) Carbodiimide.

Nonspecific adsorption (NSA) seems to be an impregnable obstacle to the progress of the biomedical, diagnostic, microelectronic, and material fields. The reaction path of bioconjugation can alter the surface charge distribution on products and the interaction of bioconjugates, an ignored factor causing NSA. We monitored exacerbated NSA introduced by a 1-ethyl-3-(3-(dimethylamino)propyl) carbodiimide (EDC) addition reaction, which cannot be resistant to bovine serum albumin (BSA) or polyethylene glycol (PEG) antifouling coating and Tween-20. And the negative effects can be minimized by adding as low as 7.5 × 10-6 M N-hydroxysulfosuccinimide (sulfo-NHS). We applied ordered porous layer interferometry (OPLI) to sensitively evaluate the NSA that is difficult to measure on individual particles. Using the silica colloidal crystal (SCC) film with Fabry-Perot fringes as in situ and real-time monitoring for the NSA, we optimized the surface chemistry to yield a conjugate surface without variational charge distribution. In this work, we propose a novel approach from the perspective of the reaction pathway to minimize the NSA of solely EDC-induced chemistry.

Evaluation of covalent coupling strategies for immobilizing ligands on silica colloidal crystal films by optical interferometry.

Immobilizing ligands is a crucial part of preparing optical sensors and directly connected to the sensitivity, stability, and other characteristics of sensors. In this work, an ordered porous layer interferometry (OPLI) system that can monitor the covalent coupling process of ligands in real time was developed. Films of silica colloidal crystal (SCC), as optical interference substrates, were surface modified by three different reagents: chloroacetic acid, glutaric anhydride, and carboxymethyl dextran. Staphylococcus aureus protein A (SPA), the ligand, was immobilized on SCC films. The covalent coupling process of SPA and SCC films can be dynamically monitored by the OPLI system. In addition, the three different strategies were evaluated by comparing the efficiency of the sensors prepared by different methods for binding Immunoglobulin G (IgG). The glutaric anhydride-modified sensor offers apparent advantages in terms of bound IgG quantity and affinity. This system provides a simple and intuitive way to determine the efficiency of different covalent coupling strategies. Furthermore, the sensor covalently coupled with SPA also excels in the determination of IgG content in complex systems such as milk. At the same time, the covalent coupling gives the sensor the ability to be stored stably over time.

Transient inhibition of CDK2 activity prevents oocyte meiosis I completion and egg activation in mouse.

Mammalian oocytes are arrested at the diplotene stage of prophase I during fetal or postnatal development. It was reported that cyclin-dependent kinases (CDK1) was the sole CDK to drive the resumption of meiosis and CDK2 was dispensable for meiosis progression in mouse oocytes according to the conditional knockout studies. However, a recent study showed that CDK2 activity is essential for meiotic division and gametogenesis by means of gene-directed mutagenesis, which avoids the compensatory activation of other CDKs. Taken the compensatory effect between CDKs after gene knockout, the physiological function of CDK2 activity in oocyte maturation remains unclear. To address this issue, we applied a specific small-molecule inhibitor to restrain CDK2 activity transiently during oocyte meiotic maturation. Surprisingly, transient inhibition of CDK2 activity severely prevented the meiosis I completion although the meiotic resumption was not affected. Then we found that CDK2 activity was required for establishment of normal spindle and chromosome dynamics. Notably, CDK2 inhibition interrupted the anaphase-promoting complex/cyclosome (APC/C)-dependent degradation pathway by maintaining the activation of spindle assembly checkpoint (SAC). Interestingly, CDK2 inhibition prevented the egg activation as well. Overall, our data demonstrate that CDK2 kinase activity is required for proper dynamics of spindle and chromosomes, whose disturbance induces the continuous SAC activation and subsequent inactivation of APC/C activity in oocyte meiosis.

Real-Time Monitoring of Curcumin Release with a Lipid-Curcumin-Loaded Silica Colloidal Crystal Film Using Optical Interferometry.

A novel efficacious strategy for real-time monitoring of the release of hydrophobic cargo curcumin (molecule model nutraceuticals) from a lipid-curcumin-loaded silica colloidal crystal (L(Cur)-SCC) film controlled by lipase was developed. Curcumin was dispersed in a proportion of a digestible lipid complex (glycerol trioleate and glycerol tristearate) to prepare a lipid-curcumin complex and then loaded into the SCC film by a capillary to prepare an L(Cur)-SCC film. Lipase-triggered degradation of the digestible lipid complex resulted in curcumin release being tracked in real-time by ordered porous layer interferometry (OPLI). The optical thickness changes (ΔOT) of the L(Cur)-SCC film depend on the mass changes of the lipid-curcumin complex due to the migration of interference fringes caused by the lipase degradation of the digestible lipid complex. Curcumin release from the L(Cur)-SCC film was characterized and analyzed in combination with an ultraviolet-visible spectrophotometer, a nanoparticle size analyzer, and an attenuated total reflection infrared spectrometer. The introduction of a soluble dietary fiber (pectin) into the L(Cur)-SCC film delayed the release rate of curcumin. Furthermore, the real-time sustained release of curcumin from the L(Cur)-SCC film in the simulated digestive fluids was tracked. This study provides an early exploration of the real-time controlled release of lipid-soluble nutraceuticals in the gastrointestinal tract.

The cyclin B2/CDK1 complex inhibits separase activity in mouse oocyte meiosis I.

Chromosome segregation is driven by separase, activity of which is inhibited by binding to securin and cyclin B1/CDK1. In meiosis, premature separase activity will induce aneuploidy or abolish chromosome segregation owing to the untimely destruction of cohesin. Recently, we have proved that cyclin B2 can compensate for cyclin B1 in CDK1 activation for the oocyte meiosis G2/M transition. In the present study, we identify an interaction between cyclin B2/CDK1 and separase in mouse oocytes. We find that cyclin B2 degradation is required for separase activation during the metaphase I-anaphase I transition because the presence of stable cyclin B2 leads to failure of homologous chromosome separation and to metaphase I arrest, especially in the simultaneous absence of securin and cyclin B1. Moreover, non-phosphorylatable separase rescues the separation of homologous chromosomes in stable cyclin B2-arrested cyclin B1-null oocytes. Our results indicate that cyclin B2/CDK1 is also responsible for separase inhibition via inhibitory phosphorylation to regulate chromosome separation in oocyte meiosis, which may not occur in other cell types.

Comparative clinical outcome following individualized follitropin delta dosing in Chinese women undergoing ovarian stimulation for in vitro fertilization /intracytoplasmic sperm injection.

BACKGROUND: To compare the efficacy and safety of follitropin delta in its individualized fixed-dose regimen with follitropin alfa in a conventional adjustable dosing regimen in Chinese women.  METHODS: This was a subgroup analysis of the randomized, multi-center, assessor-blind, non-inferiority trial (GRAPE) including 759 Chinese women (aged 20-40 years) recruited in 16 reproductive medicine clinics in China. Women were randomized in a 1:1 ratio to be treated with either follitropin delta dose based on anti-Müllerian hormone (AMH) and body weight or conventional dosing with follitropin alfa following a gonadotropin-releasing hormone (GnRH) antagonist protocol. The primary outcome was ongoing pregnancy rate assessed 10-11 weeks after embryo transfer in the fresh cycle (non-inferiority margin -10.0%). RESULTS: 378 in the follitropin delta group and 381 in the follitropin alfa group were randomized and exposed. Non-inferiority was confirmed with respect to ongoing pregnancy with rates of 31.0% vs. 25.7% for follitropin delta compared to follitropin alfa, estimated mean difference of 5.1% (95% confidence interval (CI) -1.3% to 11.5%). The clinical pregnancy rate (35.4% vs. 31.5%, P = 0.239) and live birth rate (31.0% vs. 25.5%, P = 0.101) were comparable between the follitropin delta group and the follitropin alfa group. Overall, the individualized follitropin delta treatment resulted in fewer oocytes retrieved compared to follitropin alfa treatment (10.3 ± 6.2 vs. 12.5 ± 7.5, P < 0.001), which was mainly due to fewer oocytes (10.5 ± 6.4 vs. 13.9 ± 7.8) in women with AMH ≥ 15 pmol/L. Accordingly there was a lower incidence of early ovarian hyper-stimulation syndrome (OHSS) and/or preventive interventions (6.1% vs. 11.0%, P = 0.013). A daily follitropin delta dose of 10.2 µg (95% CI: 9.3-11.2 µg) was estimated to provide the same number of oocytes retrieved as a starting dose of 150 IU/d of follitropin alfa. CONCLUSION: Follitropin delta in its individualized fixed-dose regimen showed similar efficacy and improved safety compared with follitropin alfa in a conventional adjustable dosing regimen in Chinese women. CLINICAL TRIAL REGISTRATION NUMBER: NCT03296527.

Age-specific random day serum antimüllerian hormone reference values for women of reproductive age in the general population: a large Chinese nationwide population-based survey.

BACKGROUND: Antimüllerian hormone, the most reliable biomarker of ovarian reserve, is widely used in various clinical situations. Antimüllerian hormone levels consistently decrease with age. However, there is no standard, age-specific reference values for antimüllerian hormone in women of reproductive age, which limits its application. OBJECTIVE: This study aimed to establish age-specific antimüllerian hormone percentile reference values for women of reproductive age. STUDY DESIGN: A nationwide, population-based cross-sectional survey was conducted between May 2019 and April 2021 in 15 provinces and municipalities in mainland China. A total of 10,053 eligible women aged 20 to 49 years were selected using a multistage stratified sampling procedure. Women who were pregnant, had undergone ovarian surgery, took hormone drugs in the past 3 months, or had an antimüllerian hormone outlier value were excluded from establishing antimüllerian hormone percentile reference values. Serum antimüllerian hormone concentrations were measured using ultrasensitive, 2-site enzyme-linked immunosorbent assays (Ansh Lab, Webster, TX) in the Reproductive Endocrinology Laboratory of Peking University Third Hospital. Generalized additive models for location scale and shape with the Box-Cox t original distribution were used to estimate the fitted antimüllerian hormone percentile reference values. RESULTS: A total of 9112 eligible women aged 21 to 49 years were included in the fitting model. The fitted 50th (2.5th-97.5th) percentiles of antimüllerian hormone values for women aged 21, 25, 30, 35, 40, 45, and 49 years were 4.83 (0.79-18.41), 4.47 (0.72-16.58), 3.67 (0.50-13.82), 2.59 (0.24-10.35), 1.35 (0.05-6.68), 0.33 (<0.01 to 3.40), and 0.04 (<0.01 to 1.77) ng/mL, respectively. The population-based decline rate of antimüllerian hormone accelerated with increasing age, especially age >35 years. The magnitude of the decline of the 25th antimüllerian hormone percentile curve was greater than that of the 75th percentile curve. CONCLUSION: This study established age-specific antimüllerian hormone percentile reference values for women of reproductive age based on a large representative sample of the general population and described antimüllerian hormone changes. These findings may facilitate antimüllerian hormone application in clinical practices.

Construction of Optical Interference Fibrin and Thrombolysis Analysis with Silica Colloidal Crystal Films.

Developing powerful real-time methods for monitoring the thrombolytic process is highly desirable for the early therapy of thrombus diseases. Herein, an optical interference fibrin was constructed, fabricated by assembling a 190 nm silica colloidal crystal on glass slides, for detecting a thrombolytic process through the shift of interference peaks caused by the variation of the thicknesses of a silica colloidal crystal film with loaded fibrin dissolution. The whole kinetic progress of thrombolysis by nattokinase and urokinase as thrombolytic drug models was recorded, and the kinetic data were calculated. Moreover, the developed method shows excellent sensitivity for the activity of nattokinase and urokinase with wide linear ranges of approximately 0.75-750 and 5-1000 units mL-1, respectively. Thus, this method can be used as a real-time, low-cost, and simple system for monitoring the thrombolytic process of drugs, demonstrating huge potential in the development of treating thromboembolic diseases and screening drugs.

Overexpression of cyclin A1 promotes meiotic resumption but induces premature chromosome separation in mouse oocyte.

Mammalian cyclin A1 is prominently expressed in testis and essential for meiosis in the male mouse, however, it shows weak expression in ovary, especially during oocyte maturation. To understand why cyclin A1 behaves in this way in the oocyte, we investigated the effect of cyclin A1 overexpression on mouse oocyte meiotic maturation. Our results revealed that cyclin A1 overexpression triggered meiotic resumption even in the presence of germinal vesicle breakdown inhibitor, milrinone. Nevertheless, the cyclin A1-overexpressed oocytes failed to extrude the first polar body but were completely arrested at metaphase I. Consequently, cyclin A1 overexpression destroyed the spindle morphology and chromosome alignment by inducing premature separation of chromosomes and sister chromatids. Therefore, cyclin A1 overexpression will prevent oocyte maturation although it can promote meiotic resumption. All these results show that decreased expression of cyclin A1 in oocytes may have an evolutional significance to keep long-lasting prophase arrest and orderly chromosome separation during oocyte meiotic maturation.

CDC6 regulates both G2/M transition and metaphase-to-anaphase transition during the first meiosis of mouse oocytes.

Cell division cycle protein, CDC6, is essential for the initiation of DNA replication. CDC6 was recently shown to inhibit the microtubule-organizing activity of the centrosome. Here, we show that CDC6 is localized to the spindle from pro-metaphase I (MI) to MII stages of oocytes, and it plays important roles at two critical steps of oocyte meiotic maturation. CDC6 depletion facilitated the G2/M transition (germinal vesicle breakdown [GVBD]) through regulation of Cdh1 and cyclin B1 expression and CDK1 (CDC2) phosphorylation in a GVBD-inhibiting culture system containing milrinone. Furthermore, GVBD was significantly decreased after knockdown of cyclin B1 in CDC6-depleted oocytes, indicating that the effect of CDC6 loss on GVBD stimulation was mediated, at least in part, by raising cyclin B1. Knockdown of CDC6 also caused abnormal localization of γ-tubulin, resulting in defective spindles, misaligned chromosomes, cyclin B1 accumulation, and spindle assembly checkpoint (SAC) activation, leading to significant pro-MI/MI arrest and PB1 extrusion failure. These phenotypes were also confirmed by time-lapse live cell imaging analysis. The results indicate that CDC6 is indispensable for maintaining G2 arrest of meiosis and functions in G2/M checkpoint regulation in mouse oocytes. Moreover, CDC6 is also a key player regulating meiotic spindle assembly and metaphase-to-anaphase transition in meiotic oocytes.

Using Reflectometric Interference Spectroscopy to Real-Time Monitor Amphiphile-Induced Orientational Responses of Liquid-Crystal-Loaded Silica Colloidal Crystal Films.

An approach to optical transduction and amplification of amphiphile-triggered orientational responses of liquid crystals (LCs) based on the interference effect was developed. The sensitive substrate was obtained by lading 4'-pentyl-4-cyanobiphenyl (5CB) into three-dimensionally ordered silica colloidal crystal (SCC) films. Changes in the optical thickness (ΔOT) of the substrates, which are inverted by their Fabry-Perot fringes, depend on the changes of the refractive index caused by the differences in the orientations of LCs. The orientation changes of LCs loading into SCC films have the effect of amplifying signals. These are based on the interactions between surfactants (alkyl trimethylammonium halides (CnTABs, n = 8, 10, 12, 14, and 16) and sodium lauryl sulfonate (SLS)) and LCs, which induce a particular orientation of the LCs molecules. In this flowing system, the reversibility of the signal response for the adsorption of amphiphile was related to the length of the surfactant chain and its critical micelle concentration (CMC). A new method capable of real-time sensing adsorbate-triggered anchoring transitions based on LC-infiltrated SCC films was accomplished. These results provide basics and principles for online, label-free, and real-time analysis of molecules and their interactions in a flowing environment based on the interference effect.

Interference Effect of Silica Colloidal Crystal Films and Their Applications to Biosensing.

With the aim to develop better and more reliable interference effective substrates, silica colloidal crystal films with different sphere diameters and film thicknesses were successfully made by an improved vertical deposition method and a systematic investigation of their reflectometric interference spectroscopy (RIfS) properties are presented in this work. The influence of silica sphere diameter and film thickness on the RIfS signals was studied. The results showed that the film thickness is the key factor of RIfS signals. An RIfS system was set up by using a silica colloidal crystal film as an interference effective substrate. The influence of film thickness on the response to refractive index changes of the proposed system was also investigated. When the influence of film thickness on RIfS signals and refractive index response we considered together, silica colloidal crystal films with a thickness between 4 and 6 µm were chosen for sensor construction. Monitoring the digestive process of gelatin with trypsin was also demonstrated by combining gelatin-modified silica colloidal crystal films with RIfS. The system showed excellent sensitivity with a wide linear range and could achieve real-time measurement of each process. It has been proved that this is a promising method to construct biosensors using silica colloidal crystal films as interference-sensitive substrates.