{"id":44909,"date":"2025-01-01T18:41:37","date_gmt":"2025-01-01T18:41:37","guid":{"rendered":"https:\/\/www.alicat.com\/?p=44909"},"modified":"2025-05-23T22:50:41","modified_gmt":"2025-05-23T22:50:41","slug":"atf-filtrationseffizienz","status":"publish","type":"post","link":"https:\/\/www.alicat.com\/de\/articles\/atf-filtration-efficiency\/","title":{"rendered":"ATF-Filterung verbessert die Effizienz"},"content":{"rendered":"\n[et_pb_section fb_built=”1″ theme_builder_area=”post_content” _builder_version=”4.27.4″ _module_preset=”default”][et_pb_row _builder_version=”4.27.4″ _module_preset=”default” custom_padding=”2em||0px||false|false” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.27.4″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_heading title=”Alternating Tangential Flow Filtration” _builder_version=”4.27.4″ _module_preset=”default” hover_enabled=”0″ custom_css_free_form=”selector h1 {|| padding-bottom: 0;|| text-wrap: pretty;||}” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″][\/et_pb_heading][et_pb_divider color=”#2A3B47″ divider_weight=”2.5px” _builder_version=”4.27.4″ _module_preset=”default” height=”0px” custom_margin=”3rem||3rem||true|false” global_colors_info=”{}” theme_builder_area=”post_content”][\/et_pb_divider][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.27.4″ _module_preset=”default” custom_padding=”0px||0px||true|false” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.27.4″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||2rem||false|false” hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″]Alternating tangential flow filtration (ATF) is a filtration method used in a variety of industrial applications to purify desired particles out of a sample. This technique is an optimized version of tangential flow filtration (TFF), making it useful to first develop an understanding of this original technology.[\/et_pb_text][et_pb_heading title=”What is tangential flow filtration?” _builder_version=”4.27.4″ _module_preset=”default” title_level=”h3″ hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″][\/et_pb_heading][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” module_alignment=”center” custom_margin=”||0px||false|false” custom_padding=”||2rem||false|false” custom_padding_last_edited=”off|desktop” hover_enabled=”0″ custom_css_free_form=”selector figure {|| display: table;|| margin-left: auto;|| margin-right: auto;|| text-align: center;||}||||selector figcaption {|| caption-side: bottom;|| display: table-caption;||}||||selector img {|| margin-bottom: 1rem;||}” global_colors_info=”{}” custom_css_main_element_last_edited=”on|phone” sticky_enabled=”0″ locked=”off” theme_builder_area=”post_content”]
\"Graphic\n\n
Tangential flow filtration flow path<\/figcaption>\n<\/figure>[\/et_pb_text][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||2rem||false|false” hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″]Tangential flow filtration (TFF) is a widely used separation method where particles are flowed tangential (parallel) to a filter rather than directly through a membrane. This method effectively separates out particles (the permeate) from the rest of the flow (the retentate) without quickly clogging the filter. This prevents particle build up and facilitates more complete removal of the permeate from the flow.[\/et_pb_text][et_pb_heading title=”How does tangential flow filtration work?” _builder_version=”4.27.4″ _module_preset=”default” title_level=”h3″ hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″][\/et_pb_heading][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||2rem||false|false” hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″]TFF works by applying a\u00a0pressure differential across a filter<\/a>\u00a0while continuously flowing a sample past it. As the particles pass the filter, the positive pressure on the permeate side causes particles to be pulled through. The retentate, on the other hand, continues to circulate through the system until all permeate is removed.[\/et_pb_text][et_pb_heading title=”What is alternating tangential flow filtration?” _builder_version=”4.27.4″ _module_preset=”default” title_level=”h3″ hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″][\/et_pb_heading][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||2rem||false|false” hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″]Alternating tangential flow filtration uses a similar technique as TFF. The primary difference is that ATF is a perfusion process, designed to minimize\u00a0filter fouling<\/a>.\n\nIn ATF, the permeate is removed to a collection while a diaphragm pump alternates between positive pressure and vacuum to move the retentate back and forth across the membrane. The\u00a0retentate returns to the bioreactor<\/a>\u00a0between each cycle, mixing with the next fluid batch to be filtered. ATF is ideal for collecting the desired product within the permeate, as the retentate is continually pushed back into the bioreactor.\n\nThe alternating flow of the retentate cleans the filter, enabling it to be used much longer or for larger batches than equivalent TFF filters.[\/et_pb_text][et_pb_heading title=”Filter characterization in tangential flow filtration” _builder_version=”4.27.4″ _module_preset=”default” title_level=”h3″ hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″][\/et_pb_heading][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||2rem||false|false” hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″]

Hollow fiber and cassette membranes are the two most common membranes for flow filtration. Hollow fiber membranes are cylindrical, with the membrane embedded as fibers in the cylinder. The fluid passes through the cylinder, with ports to separate permeate and retentate at either end of the cylinder. Cassette membrane layers are stacked and separated by screens. The fluid is flowed through the layers and the permeate is removed out of the side, while the retentate continues to flow.<\/p>\n

Membranes are classified by their average pore size. Those used in bioprocessing are generally for either microfiltration or ultrafiltration. Microfiltration membranes have pores with diameters greater than 0.1 \u00b5m, and are generally used to separate proteins and other small molecules from cells (the larger cells are discarded in the retentate). Ultrafiltration membranes have pores with diameters smaller than 0.1 \u00b5m, and are often used to concentrate proteins. The proteins are in the retentate in this case, while water and various small solutes are discarded in the permeate.<\/p>[\/et_pb_text][et_pb_heading title=”Advantages of tangential flow filtration over dead-ended methods” _builder_version=”4.27.4″ _module_preset=”default” title_level=”h3″ hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″][\/et_pb_heading][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||2rem||false|false” hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″]

Dead\u2011ended filtration flows samples directly through a membrane, oftentimes resulting in a clogged filter. The tangential flow of TFF prevents clogging and is much faster and more efficient than traditional filtration methods.<\/p>\n

In TFF, the flow stream with the desired product can be recycled and looped through the system as many times as necessary for complete separation of the permeate and retentate. This process can also be used to clean the filter, by flowing pure buffer through the system.<\/p>\n

As with dead\u2011ended filtration, the size of the membrane pores determine which particles are able to pass through the membrane. Pore size can be optimized to isolate the desired particles either in the permeate or the retentate.<\/p>[\/et_pb_text][et_pb_heading title=”Applications that use tangential flow filtration” _builder_version=”4.27.4″ _module_preset=”default” title_level=”h3″ hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″][\/et_pb_heading][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||2rem||false|false” hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″]