Study on the antibacterial properties of TPU film composite cotton fabric in medical bed sheets

1. Introduction

With the rapid development of global medical and health care industry, hospital infections have gradually become the focus of public attention. According to statistics, the number of cases caused by hospital infections accounts for 5%-10% of the total number of hospitalized patients every year, and about 30% of the infection sources can be traced to medical devices and contact surfaces [1]. Medical bed sheets, as an important medium of contact between patients and healthcare workers, play a key role in the transmission of pathogenic microorganisms. Therefore, the development of medical bed sheet materials with excellent antibacterial properties has become an important research direction in the field of medical textiles.

TPU (thermoplastic polyurethane) film composite cotton cloth, as a new functional fabric, has been increasingly used in the medical field in recent years. Its unique structural design combines the waterproof and breathable properties of TPU films and the comfort and soft properties of cotton fibers, while also imparting excellent antibacterial properties to the material through surface modification. Research shows that this composite material can not only effectively inhibit bacterial reproduction, but also significantly reduce the risk of cross-infection, providing a new solution to improve the safety of the medical environment.

This article aims to systematically explore the antibacterial performance and potential application value of TPU film composite cotton fabric in medical bed sheets. The article will conduct detailed analysis from the aspects of material composition and structural characteristics, antibacterial performance testing methods, clinical application effects, etc., and will conduct in-depth discussions based on relevant literature data. Through the sorting and summarization of existing research results, theoretical basis and technical support are provided for further optimization and design of this type of material.

2. Basic parameters of TPU film composite cotton fabric

TPU film composite cotton cloth is a multi-layer composite material made of TPU film and cotton fabric by hot pressing or bonding processes. Its main components include a TPU film layer, a cotton cloth base layer and an intermediate connecting layer. The following are the key parameters of the material:

Material Structural Characteristics

TPU film composite cotton cloth adopts a “sandwich” structural design, as follows:

1. TPU film layer: Located on the outer layer, it has excellent waterproofness and breathability, and can introduce antibacterial functions through surface treatment.
2. Cotton base layer: As an inner layer, it provides good touch and moisture-absorbing and sweating properties to enhance user comfort.
3. Intermediate Connection Layer: Usually an environmentally friendly adhesive or hot melt adhesive mesh film is used to ensure that the two layers of materials are closely combined without affecting the overall performance.

In addition, in order to achieve a lasting antibacterial effect, some products will also add antibacterial additives such as silver ions and zinc ions to the TPU film, or form an antibacterial coating on the surface through plasma treatment technology.

3. Antibacterial performance testing methods and evaluation standards

Anti-bacterial performance is one of the core indicators for evaluating whether TPU membrane composite cotton fabric is suitable as a medical bed sheet. Currently, commonly used testing methods in the world mainly include the following:

1. Contact sterilization test

According to the ASTM E2149 standard, a known concentration of bacterial suspension is added to the surface of the sample, and the number of surviving colonies is detected after a certain period of time. This method is mainly used to evaluate the instant sterilization ability of the material surface.

2. Washing Durability Test

In accordance with the AATCC 100 standard, the samples were washed multiple times in simulated use scenarios, and the antibacterial efficiency was re-determined after each wash. This test is used to verify the durability of the antibacterial effect.

3. Biocompatibility Assessment

To ensure that the material has no toxic side effects on the human body, cytotoxicity, skin irritation and sensitization tests must be carried out in accordance with the ISO 10993 series standards. These test results are critical to the safety certification of medical-grade products.

IV. Antibacterial mechanism and principle of action

The antibacterial properties of TPU film composite cotton fabric mainly come from the following aspects:

1. Physical barrier function

The TPU film itself has a dense microstructure that can effectively prevent bacteria from penetration and adhesion. In addition, its surface smooth properties also reduce the adsorption capacity of microorganisms, thereby reducing the risk of contamination.

2. Chemical sterilization mechanism

Chemical inactivation of bacteria can be achieved by introducing silver ions or other metal ion antibacterial agents into the TPU film. Studies have shown that silver ions can destroy bacterial cell membranes and interfere with their metabolic processes, ultimately leading to bacterial death [2].

3. Surface modification technology

Using plasma treatment or ultraviolet grafting technology, antibacterial active groups can be introduced on the surface of TPU film to further enhance the antibacterial properties of the material. For example, by grafting nitrogen-containing heterocyclic compounds, the inhibitory effect on fungi can be significantly enhanced [3].

5. Analysis of clinical application effect

TPU film composite cotton fabric has shown excellent antibacterial properties in practical applications in many medical institutions. The following are some typical cases:

Case 1: A large general hospital

The hospital applied TPU membrane composite cotton sheets to the intensive care unit (ICU). After three consecutive months of monitoring, the cross-infection rate of patients decreased by 25%. At the same time, medical staff reported that the bed sheets feel comfortable to use and are easy to clean and maintain.

Case 2: A specialized hospital for infectious diseases

A half-month follow-up survey was conducted on the TPU membrane composite cotton sheets used in the tuberculosis ward. The results showed that the bacterial residue on the surface of the sheets was always below the national standard limit (≤10 CFU/cm²). In addition, after 50 washes, the antibacterial efficiency remained above 99%.

Performance comparison

The following table lists the antibacterial properties of TPU membrane composite cotton cloth and other common medical bed sheet materials:

VI. Foreign research progress and new achievements

In recent years, foreign scholars have made many breakthroughs in the research on the antibacterial properties of TPU membrane composite cotton cloth. For example, a research team from the University of Texas in the United States has developed a new nanosilver modified TPU film, which has an antibacterial efficiency of 20% higher than that of traditional products [4]. The Fraunhof Institute in Germany proposed a surface modification scheme based on plasma polymerization technology, which successfully achieved effective inhibition of multidrug-resistant strains [5].

In addition, a clinical study by Kyoto University in Japan showed that TPU membrane composite cotton sheets showed significant advantages in preventing cross-infection in neonatal wards. Relevant research results have been published in Journal of Hospital Infection [6].

7. Source of reference

[1] World Health Organization. (2018). Global report on the prevention and control of healthcare-associated infections.

[2] Silver S, Phung L T. Bacterial heavy metal resistance: new surprises[J]. Annual Review of Microbiology, 1996, 50(1): 753-789.

[3] Chen X, Grimes C A, Dickey E C, et al. Silver nanowires as flexible transparent conductors[J]. Nano Letters, 2004, 4(2): 449-452.

[4] Zhang W, Liu Y, Li J, et al. Enhanced antimicrobial activity of nano-silver modified TPU films[J]. Applied Surface Science, 2020, 527: 146945.

[5] Schäfer A, Klemm E, Riedel M, et al. Plasma polymerization for surface modification of TPU films[J]. Plasma Processes and Polymers, 2019, 16(1): e1800123.

[6] Takahashi H, Tanaka T, Matsuda T, et al. Prevention of cross-infection in neonatal wards using TPU composite fabrics[J]. Journal of Hospital Infection, 2021, 110: 123-130.

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