• Polymer(Korea)
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• v.36 no.2
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• pp.190-195
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• 2012

Interfacial and rheological properties of selected hydrogel formulations were studied to understand the contact-lens comfort in end use. It was concluded that protein adsorption from aqueous solution decreased monotonically with increasing surface energy (water wettability) of tested hydrogels. Also, it has revealed that friction coefficient of polydimethylsiloxane-polyvinylpyrrolidone (PDMS-PVP) was significantly larger that 2-hydroxyethyl methacrylate (HEMA) based hydrogels. Interestingly, in artificial tear solution, friction coefficients of HEMA based hydrogels were larger than silicone hydrogels.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.3
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• pp.215-225
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• 2016

Purpose: The aim of this study was to figure out how the characteristics of soft contact lens materials and pigmentation affect the adherence of C. albicans on soft contact lenses pre-deposited with tear constituents. Methods: The adherent number of C. albicans on clear soft contact lenses (hereinafter clear lenses) and circle soft contact lenses (hereinafter circle lenses) made of etafilcon A, hilaiflcon B and nelfilcon A, respectively, was measured before and after the deposition of artificial tear. Also, bacteria adherence on lenses were observed by a scanning electron microscope. Results: Adherence of C. albicans was significantly different according to lens materials. The amount of adsorption was not different between clear lenses and circle lenses made of etafilcon A however, the number of bacteria absorption was bigger in hilafilcon B and nelfilcon A lenses. More absorption of C. albicans was found in the non-pigmented central area compared the pigmented area, and non-pigmented peripheral area has more bacterial absorption than non-pigmented central area. The number of C. albicans decreased in the case that tear protein was pre-deposited. The maintenance of antibacterial activity against C. albicans was different according to lens materials thus, etafilcon A has the longest period of its maintenance. Conclusions: It was revealed that the number of C. albicans was different according to the characteristics of lens materials, pigmentation or non-pigmentation, the pigmented area of soft contact lenses. Thus, it is suggested that the management method should be different according to the adsorption characteristics of C. albicans.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.1
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• pp.35-42
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• 2015

Purpose: The present study was aimed to compare the difference in adherence level of microorganisms according to contact lens materials and protein deposition and to evaluate disinfection efficacy of multipurpose solution. Methods: The evaluations of micro-organisms' adherence and disinfection efficacy of multi-purpose solution were conducted by employing the Part 2. Regimen Procedure for Disinfecting Regiments in the Disinfection Efficacy Testing under the "FDA Evaluation Criteria & Method". Results: Pseudomonas aeruginosa, Serratia marcescens, Candida albicans except Staphylococcus aureus adhered more on etafilcon A lens and disinfection efficacy of total 4 products investigated was almost perfect except Candida albicans. The 3 micro-organisms except Serratia marcescens adhered more to albumin-predeposited lens. Disinfection efficacy of multi-purpose solution was higher against the micro-organisms adhered to albumin-deposited lens than against the micro-organisms adhered to the lysozyme-deposited lens. Furthermore, disinfection efficacy of multi-purpose solution was different according to types of micro-organisms. Conclusions: It was revealed that the type of micro-organisms, the lens materials and type of absorbed tear protein affected the amount of adhered micro-organisms to contact lens and that adhesion of tear protein could induce the change of disinfection efficacy of multi-purpose solution. It suggest that the hygienic condition of contact lens can vary by these factors influencing on disinfection efficacy and the occurrence of adverse effect can be affected.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.2
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• pp.109-117
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• 2016

Purpose: The study was aimed to figure out the effect of materials and pigmentation of soft contact lens on the adherence of Staphylococcus aureus upon soft contact lenses deposited with tear components. Methods: The number of adherent S. aureus on clear and circle soft contact lenses made of etafilcon A, hilafilcon B, nelfilcon A was measured before and after incubation in artificial tear. Furthermore, the denaturalization level of tear protein with time after incubation in artificial tear was estimated by electrophoresis. Results: The adherence of S. aureus was significantly different according to the lens materials. The pattern of bacterial adherence on clear and circle contact lenses was different. That is, the adherent amount of S. aureus was somewhat larger on circle lens made of etafilcon A however, amount on circle lenses made of hilafilcon B and nelfilcon A was 89.3% and 71.3% of the number on clear lenses. When the tear protein was deposited on contact lenses, the number of adherent bacteria decreased and its degree was varied according to the lens material. The degree of decrease was the biggest in clear soft lens made of etafilcon A. Anti-bacterial effect of tear protein decreased with time after deposition of tear protein on soft contact lens and the amount of lysozyme also decreased. The reduction of anti-bacterial effect and quantity of lysozyme was different according to contact lens materials and pigmentation. Conclusions: It was revealed that the adherence of S. aureus depends on contact lens materials and pigmentation, and the specification of lens material affects more on adherence of S.aureus than pigmentation. It was further figured out the denaturalization level of anti-bacterial protein on soft contact lens varies according to lens materials and pigmentation, which produces an effect on the quantity of bacterial adherence.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.261-270
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• 2013

Purpose: Adsorption properties of lysozyme and albumin according to physiochemical properties of commercial contact lens classified with the FDA categories and a contact lens fabricated in the laboratory were investigated. Methods: The contact lens were prepared using HEMA(2-hydroxyethyl methacrylate) and TRIM(3-(trimethoxysilyl) propyl methacrylate) in a cast mold. Artificial tears containing lysozyme and albumin were prepared. We measured the amounts of protein adsorbed on the each lenses with varying adsorbed time (48 hour) and the pH range (6, 6.8, 7.4, 8.2, 9) of artificial tear. Amount of the proteins absorbed on the contact lenses were measured by using HPLC. Results: Time to reach the equilibrium of protein adsorption for silicone hydrogel lens was taken longer than hydrogel lens. The amount of adsorbed both lysozyme and albumin at equilibrium were greater for the hydrogel lens than the silicone hydrogel lens, and larger for the ionic lens than the non-ionic lens. Lysozyme was more adsorbed on the higher water content of contact lens, whereas albumin was more adsorbed on the lower water content of contact lens. Only lysozyme was adsorbed on the Group IV hydrogel lens of ionic higher water content. The adsorption of protein on contact lens increased with pH of artificial tears as close to the isoelectric point of each protein. Conclusions: The adsorption amount of lysozyme is more affected by the ionic strength of the contact lens surface than the water content of contact lens. Albumin adsorption is more affected by water content than the ionic strength of the contact lens surface. For the adsorption of proteins on the silicone hydrogel lens, the pore size, determined both by the number of Si atoms and the chemical structure of the silicone-containing monomers, as well as the polarity of contact lens should be also considered.

• Polymer(Korea)
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• v.33 no.2
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• pp.169-174
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• 2009

Silicone hydrogels incorporated with poly(ethylene glycol)(PEG) were prepared and characterized to evaluate the effects of PEG on contact lenses. The silicone hydrogels were copolymerized with methacryloxypropyl tris(trimethylsiloxy) silane (TRIS), methyl methacrylate (MMA), N,N-dimethyl acrylamide (DMA) and PEG-containing monomers such as poly(ethylene glycol) methyl ether methacrylate (PEG- MEM). The silicone hydrogels were characterized using Fourier transform infrared spectroscopy (FT-IR), electron spectroscopy of chemical analysis (ESCA), and scanning electron microscopy (SEM). Water absorbance, water contact angle and light transmittance of the silicone hydrogels were evaluated. The experiments of protein adsorption were also carried out to evaluate the protein adsorption in tears. The peak intensity of C-O bond was increased by the incorporation of PEG-containing monomers and thus PEG incorporation into silicone hydrogels could be confirmed. Phase separation was not shown by the SEM observation of the cross-section of silicone hydrogels. Water absorbancy was increased, while water contact angle and light transmittance were decreased with increasing incorporation of the PEG-containing monomers. The absorption of proteins in tears, albumin, lysozyme and $\gamma$-globulin, on the surface of silicone hydrogels was decreased with increasing incorporation of the PEG-containing monomers.

• Prospectives of Industrial Chemistry
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• v.22 no.6
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• pp.13-25
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• 2019

건강한 미래, 건강 사회 구현과 함께 질병 진단, 치료, 예방에 대한 관심이 급증하고 있다. 이에 따라 적시적기에 질병을 치료하고 예방하기 위한 건강 검진용 바이오센서 수요가 증가하였고 이에 따라 바이오센서 시장은 전세계적으로 급격히 확장되고 있다. 혈액 샘플을 기반으로 한 검진 방법이 보편적이지만 최근에는 고감도 센서 개발에 따라 소변, 침, 눈물 등과 같은 체액으로도 검진이 가능한 환자 친화적 비침습 센싱 방법도 활발하게 연구되고 있다. 이러한 센서 시장 패러다임의 변화 및 급속한 발전은 마이크로, 나노 재료 제작과 분석 기술 발전으로 체액 내 존재하는 나노 크기의 바이오 마커(단백질, 유전자, 펩타이드, 사이토카인)를 검출하는 소형화된 고감도의 센서를 개발할 수 있게 되었고 그 결과 화학, 물리, 재료, 의약 등 다양한 학문 분야에서 다양한 형태의 센서가 활발히 보고되었다. 본 기고문에서는 바이오센서용 소재 중에서 나노입자에 집중하여 첨단 센서 구현을 위해 사용된 입자의 종류, 센서 내에서의 입자의 역할을 소개하고 나노입자의 광학적, 물리적 특성에 따른 타겟 물질 검출 방법 및 동향에 대해 논의하고자 한다.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.285-291
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• 2015

Purpose: The hydrogel lenses have been functionalized with HA(Hyaluronic Acid) using two different methods: construction of an IPN(Interpenetrating Polymer Networks) and formation of CCB(Chemical Covalent Bonding). The lysozyme adsorption and physical properties such as optical transmittance and water content of the hydrogel lenses have been investigated in order to determine whether method is suitable for the application potentials in contact lens industry. Methods: HA have been added to the hydrogel lenses prepared in the Lab using the two different method, e.g. IPN and CCB. The optical transmittance was measured in the wavelength range of 300~800 nm. The water content was measured by the gravimetric method using 0.9% NaCl saline solution. The amounts of adsorbed lysozyme on the contact lenses was analyzed by HPLC after incubation for 12h in artificial tears. Results: The water content of the HA added hydrogel contact lenses was increased, and the lens made by IPN method showed higher water content than the lens made by CCB method. The optical transmittance was over 90% both before and after addition of HA. Comparing the lysozyme adsorption reduction ratio, contact lens manufactured by IPN method was 60.0%, and the lens made by CCB method was 40.4%. Conclusions: CCB method is appropriate to distribute the functional material evenly throughout the lens, whereas IPN method is effective for the case of giving the functionality on the lens surface without phase separation.